Patriots fan trigger warning: No modern Patriots team made this countdown. 

It's not that Bill Belichick's defenses haven't been great in the last 15 years. Heck, they would dominate the second tier of a top-50 countdown. It's just that the modern Patriots lack something most of the historic defenses on this list had to cope with: lousy quarterbacking.

Just as our countdown of All-Time Great Offenses featured teams overcompensating for suspect defenses, this list is full of teams that needed to record shutouts and score on pick-sixes to win because their too-old, too-young, too-injured or just too-terrible quarterbacks didn't win the game for them.

So really, it's Tom Brady's fault that the Patriots aren't on this list. Send him your angry emails.

These defenses are partially ranked according to stats, from points and yards allowed to sacks, turnovers and the advanced stuff tracked by Football Outsiders' all-time DVOA list. Everything is adjusted for era, of course, so this is not just a countdown of late '60s and mid-'70s defenses. Playoff dominance also counts, as does impact: Teams that transformed football strategy or fielded a bunch of Hall of Famers take precedence over teams that put up great numbers for a year or two.

As with all of these countdowns, there's a "shadow effect" in place. The Steel Curtain Steelers are represented by one year that illustrates their other great years. That way, we can tell some other stories. Of course, those Steelers get bonus points for their dynastic dominance.

Finally, teams from before the dawn of the AFL-NFL era (1960) were omitted from this countdown, though they were included in some others. The Canton Bulldogs allowed 15 points in 12 games in 1922. But no one remembers, and only a handful of us really care.

Without further ado, let's meet some all-time great defenses...as well as some of the all-time strange and unfortunate quarterback situations that made many of them necessary.

25. New York Jets, 2009

The Jets played in back-to-back AFC championships less than a decade ago, beating Carson Palmer's Bengals and Philip Rivers' Chargers in 2009 and Peyton Manning's Colts and Tom Brady's Patriots in 2010 playoff games. They did all of this with Mark Sanchez at quarterback.

The preceding paragraph should silence any doubts about whether the 2009 Jets defense belongs on a top-25 countdown.

Darrelle Revis became his own island in 2009, intercepting six passes while Jets opponents threw just eight touchdowns. Seven different opponents were held to 10 points or less. Sanchez coughed up 20 interceptions as a rookie, but the Jets allowed the fewest points and yards in the league, despite all the extra opportunities their offense gift-wrapped for opponents.

Rex Ryan's scheme combined old-school 46-defense principles with modern, conservative concepts like dropping eight defenders into zone coverage. Ryan mixed and matched defenders like David Harris (shown with Ryan), Calvin Pace, Bart Scott and others in ways not even savvy opponents were able to account for.

The Jets released the last holdovers to this era in the offseason, and Ryan was making the wrong kind of headlines a few weeks ago while his peers were coaching OTAs. But it wasn't very long ago that great defense made the Jets innovators and contenders. Life, as they say, comes at you fast.

24. New Orleans Saints, 1992

The Saints went 20 years without a winning team before the Dome Patrol arrived. Then, almost overnight, they became contenders.

The collapse of the USFL in 1986 made it happen. Jim Mora, coach of the back-to-back USFL champion Philadelphia/Baltimore Stars, came to New Orleans with his secret weapon, pint-sized inside linebacker Sam Mills. Vaughan Johnson also arrived from the NFL's ill-fated challenger. The Saints added Pat Swilling in the draft. Rickey Jackson was already the defense's only real star. The Saints reached the playoffs for the first time in franchise history in 1987, then proved it was no fluke with a string of winning seasons.

The Dome Patrol peaked in 1992, allowing just 12.6 points per game. Jackson recorded 13.5 sacks, Swilling 10.5. Defensive end Wayne Martin led the team with 15.5 as the Saints finished the year with 57 total sacks.

Many of the great defenses coming up on this countdown were either saddled with lousy offenses or stuck in the same division as a historic, legendary powerhouse. The Saints offense was pretty good in the Dome Patrol era: quarterback Bobby Hebert provided authentic Cajun spice, and Morten Andersen made sure the Saints came away from every scoring opportunity with at least a field goal.

But the Saints were trapped behind the Joe Montana-Steve Young 49ers for Mora's entire tenure. In 1992, they lost to the 49ers by scores of 16-10 and 21-20 in the regular season, with Young leading a fourth-quarter comeback from a 20-7 deficit in the second game. The Saints faced a tough Eagles team in the playoffs, their offense committed four turnovers, and nothing would ever be the same again for the Dome Patrol Saints.

The Saints never won a playoff game in the Dome Patrol era. But they gained an identity and some dignity. Their linebacker corps was one of history's best, and it made the Saints one of the NFL's "toughest outs" for over half a decade.

23. Chicago Bears, 1963

The fellow on the left in the photo above is Bill George. On the right is Doug Atkins.

George is credited as the first true middle linebacker in NFL history. In the mid-'50s, he began dropping from his "defensive center" position before the snap so he could better read the offense and flow to the football.

The 6'8" Atkins had been a basketball player and an SEC champion high jumper at Tennessee. He was unstoppable on the field and off: Atkins kept a pit bull named Rebel in his room during training camp to make coaches think twice about bed checks when he was out on the town.

With the help of stars like Joe Fortunato, Richie Petitbon and Rosey Taylor, George and Atkins held opponents to a total of 21 points in one four-game stretch. Only two opponents scored 20-plus points on them the whole season. Petitbon and Taylor combined for 17 of the team's 36 interceptions, with Atkins literally hurdling blockers at times to make quarterbacks antsy about getting rid of the ball.

The Bears won the NFL championship in 1963, intercepting Y.A. Tittle five times to beat the Giants in the title game. Young Mike Ditka was the only star on offense. Unless you are a Bears fan over 50, you probably could not name the team's quarterback given 50 guesses.

George became the spiritual father of all middle linebackers, but particularly the great ones the Bears have fielded for decades: Dick Butkus, Mike Singletary, Brian Urlacher. Atkins hurdled and caroused his way into the Hall of Fame. The Bears established the formula for success that would define them for decades: outstanding defense, a touch of rowdiness and quarterback play that stops just short of being counterproductive.

(The quarterback of the 1963 Bears was Billy Wade.)

22. Tennessee Titans, 2000

Ladies and gentlemen, Jeff Fisher made one of our all-time great countdowns!

And folks, did he ever earn it. The 2000 Titans defense allowed just two offensive touchdowns in the final six weeks of the year. Jevon Kearse recorded 11.5 of the team's 55 sacks. Samari Rolle added seven interceptions. Strong safety Blaine Bishop was an enforcer against the run and a dangerous pass-rusher in the box.

Fisher and Gregg Williams took Buddy Ryan's "46" defense, tightened up the loose screws and adapted it to a league in which spread formations and quick passing were making blitz-the-house tactics obsolete. The updated scheme provided most of the mayhem of Ryan's old tactics without the mistakes, and Fisher married it to a plodding-but-consistent offense led by Steve McNair and Eddie George. The Titans beat opponents with turnovers, field goals and field position, and it was a good thing.

As fate would have it, Fisher's all-time top-25 defense was stuck in the same division as an all-time top-10 defense. The Titans held the Ravens to just 134 yards of offense and six first downs in the playoffs. But the Ravens scored 14 points on a blocked field goal and a Ray Lewis pick-six, and the Titans endured a 24-10 playoff loss.

The title of this series is "NFL Nostalgia," and nothing brings on the feels quite like harkening back to the days when Fisher was considered a great coach. It wasn't that long ago. And it was legit. This defense nearly shut down the Rams in the Super Bowl in 1999. In 2000, it only met its match when it faced the Ravens.

21. Tie: The Fightin' 77s.

NFL teams officially gave up trying to score in 1977. Defenses had been slowly gaining control of the league for years, but in 1977 they just took over. Scoring dipped to 17.2 points per team per game; passing to 141.9 yards per game, with 40 percent more interceptions than touchdowns.

So many great defenses stormed across the league in 1977 that listing them all would eat up half of this countdown. So let's honor them all at once so we can move on and tell some other stories:

• The Steel Curtain Steelers: Yeah, they will get their own listing later, though for a different season.

• The Fearsome Foursome Rams: An earlier version of the Fearsome Foursome also gets its own listing later. This iteration, featuring Jack Youngblood, Fred Dryer, Larry Brooks, Cody Jones, Isiah Robertson and Monte Jackson, held opponents to 10.4 points per game and recorded three shutouts in 14 games.

• The Orange Crush Broncos: Randy Gradishar led a contentious cohort of marauders (Lyle Alzado, Louis Wright, Tom Jackson) to a 12-2 record and the Super Bowl, intercepting 25 passes and holding six opponents to a touchdown or less.

• The Grits Blitz Falcons: Led by pass-rusher Claude Humphrey and cornerback Rolland Lawrence and masterminded by young defensive assistant Jerry Glanville, the Falcons allowed just 9.2 points per game. The team's offense (led by Scott Hunter and a very young Steve Bartkowski) was a disaster, so the Falcons lost games by scores like 3-0, 10-3 and 10-6 en route to a .500 record.

• The Flex Defense Cowboys: The Cowboys won the Super Bowl in 1977, recording 53 sacks behind a defensive line of Randy White, Harvey Martin, Jethro Pugh and Ed "Too Tall" Jones. The Cowboys won two playoff games by a combined 60-13 score, then intercepted Craig Morton four times and sacked him four more to beat the Broncos in the Super Bowl. This defense finished first in the league in yards allowed in 1977, no small feat considering the league-wide dominance on that side of the ball.

Darn, we are almost out of room and did not get to the Sack Pack Colts, the Luv Ya Blue Oilers or any of the other teams that posted eye-popping numbers in 1977. Long story short: The NFL rewrote the rulebook to give offenses a fighting chance in 1978. Within a few years, catchy nicknames for defenses became much rarer.

20. San Francisco 49ers, 1984

Hey look: The 1984 49ers have made another NFL Nostalgia countdown! We've already talked about the brilliance of Bill Walsh and Joe Montana ad nauseum in other segments. Now it's time to heap praise on George Seifert and one of the best secondaries in NFL history.

Ronnie Lott, Eric Wright, Dwight Hicks and Carlton Williamson all made the Pro Bowl in 1984. The 49ers notched 25 interceptions, with a pass rush led by Dwaine Board and an aging Fred Dean adding 51 sacks. While Walsh pioneered the West Coast Offense, Seifert confused opponents with wrinkles like what is now called a Leo edge-rusher (a linebacker or defensive end standing up, wide of the left tackle) and what he called a Whip safety (today's safety-linebacker hybrid) on passing downs.

With both their offense and defense firing at full throttle, the 1984 49ers rung up lots of 35-3, 41-7 and 51-7 blowout wins. But they also won some games by 14-5 and 21-9 margins, proving that the defense could take care of business even when the West Coast Offense was sputtering a bit.

The 49ers defense sacked Bears backup quarterback Steve Fuller eight times in a 23-0 shutout in the NFC Championship Game. Then they took down the nearly unsackable Dan Marino four times in the Super Bowl, using a full-time 4-1-6 formation (with that Whip safety as one of the six) to counter Miami's previously unstoppable offense.

The 1984 49ers secondary was as good or better than the Legion of Boom, the 1960s Lions or any other secondary you can name. Seifert was as clever as any of history's great masterminds. They just were overshadowed in their own locker room by an offense that was changing football forever.

19. Oakland Raiders, 1967

The Raiders recorded 67 sacks and 30 interceptions in 14 games in 1967. In other words, they recorded four or five sacks and two or three interceptions on any given Sunday. The average opposing quarterback had a disastrous week every time he faced the Raiders.

You probably know that AFL passing statistics can get a little kooky, and they can take interception and sack totals with them. Well, this is the late-era AFL, when the two leagues shared a common draft and things had settled down somewhat. The Raiders weren't facing a bunch of CFL has-beens every week. They faced quarterbacks like Len Dawson, Bob Griese, John Hadl and Joe Namath. Those great quarterbacks combined for 18 interceptions in seven games against the Raiders.

Tackle Tom Keating and 6'8" end Ben Davidson anchored the defensive line and defined what would become the Raiders image, both on the field and off. (When not sacking the likes of Dawson, they took motorcycle trips to Mexico and Panama together.) Hall of Famer Willie Brown (shown) and fellow cornerback Kent McCloughan were early proponents of bump-and-run coverage. Opposing receivers were knocked all over the field. Opposing quarterbacks paid the price.

The Raiders would field great defenses well into the 1980s, with ever-changing personnel and tactics. This defense dominated its league like no other and set the tone for the next 20 years of Raiders football. These Raiders fell short of the Packers in Super Bowl II. But everyone fell short of the Packers in the 1960s.

18. Denver Broncos, 2015

No great defense on this countdown arrived more suddenly or unexpectedly than the 2015 Broncos.

The nucleus of this defense had been together and playing well for years. The Broncos reached the Super Bowl in 2015, after all. But this defense was always overshadowed by Peyton Manning's offense. Then, Manning himself became a shadow. That's when this defense took its place in the spotlight.

The individual statistics were unspectacular. Von Miller recorded 11 sacks, a low total by his standards. The secondary, led by Aqib Talib, Chris Harris and T.J. Ward, provided only 14 interceptions, though they had a knack for producing pick-sixes when the Broncos needed them most. The 2015 Broncos defense was a team effort spurred by coordinator Wade Phillips, whose schemes got the most from every player on the defensive depth chart and generated big plays in bunches.

This group left its most lasting mark in the Super Bowl, when it pulled the rug out from under the Panthers, who stormed through the regular season looking like a Team of Destiny. It was a striking contrast to the Super Bowl humiliation the high-octane Broncos of 2013 endured. The new identity suited the franchise and pointed the way toward the post-Manning era for the Broncos.

Miller and the nucleus of this defense remain intact. Who knows what the future holds? Perhaps this very countdown holds some answers. 

17. Baltimore Colts, 1971

The Colts reached Super Bowl III with an all-time great team in 1968, only to lose the game to an era-defining upstart: Joe Namath's groovy Jets. 

Two years later, the 1970 Colts defense, with quarterback Johnny Unitas on his last legs, led the team to an ugly victory in Super Bowl V.

The Colts defense was better than ever in 1971, when it allowed just 140 points in 14 games. Bubba Smith (shown), Ted Hendricks and Mike Curtis anchored the front seven that allowed just 3.2 yards per rush. Rick Volk and Charlie Stukes were the stars of a secondary that allowed just nine touchdown passes while recording 28 interceptions. But quarterback woes (the aging Unitas was still gimping around) doomed the 1971 Colts to a 21-0 loss to the Dolphins in the conference championship.

Any similarities between the 1968-71 Colts and the recent Broncos are purely intentional. The Colts even changed coaches before returning to the Super Bowl, with Don McCafferty replacing Don Shula, just as the Broncos replaced John Fox with Gary Kubiak and Wade Phillips.

Well, the early-'70s Colts soon replaced McCafferty over a quarterback controversy, just as the Broncos replaced Kubiak. First-round pick Bert Jones battled second-chance prospect Marty Domres for the right to replace Unitas. Domres held the upper hand early but soon bottomed out. By the time Jones seized the starting job and Ted Marchibroda arrived to restore order, the Colts endured three years of losing seasons in which they cycled through four head coaches, including general manager Joe Thomas, who took the reins for a while.

Again, there are some eerie Broncos precursors and portents here.

As an organization, the current Broncos are much more stable than the 1970s Colts. But if John Elway takes over as head coach because he doesn't like how the Trevor Siemian-Paxton Lynch controversy is playing out, you know history is repeating itself.

But back to the 1971 Colts. They registered three shutouts and held three other teams (including the Browns in the playoffs) to just a field goal. They deserved an offense that wasn't falling apart around them. So did many other defenses on this list. So do some current NFL teams.

16. Chicago Bears, 2005

The Bears reached the Super Bowl in 2006 in spite of their offense when their defense and special teams overcame sheer incompetence at quarterback to win 13 games.

Statistical analysis reveals that the Bears defense was actually better in 2005, when the team won 11 games but lost to the Panthers in the postseason. Maybe they just put up better numbers because they weren't shell-shocked by an offense that kept giving the ball back to opponents. Or maybe this is just nitpicking. After all, the cast of characters—Brian Urlacher, Lance Briggs, Charles Tillman, Mike Brown—was the same in both seasons.

Tillman and Nathan Vasher combined for 13 interceptions in 2005. Briggs, Brown, Tillman and Vasher all returned interceptions for touchdowns to help out the Kyle Orton-led offense. Urlacher recorded 97 solo tackles and six sacks. Eight opponents were held under 10 points. The Bears beat Brett Favre's Packers, 19-7, during the regular season on four field goals and Vasher's late-game pick-six while Orton went 6-of-17 for 68 yards. It was that kind of year.

The 2005 Bears defense buckled against the Panthers in the playoffs, allowing a pair of long touchdowns by Steve Smith in a 29-21 loss. They returned the next year with an even less reliable quarterback (Rex Grossman) but a new way of scoring without the offense's help (kick returner Devin Hester). Pick the 2006 defense over the 2005 unit if you'd like. But imagine what these defenses might have done if paired with competent quarterbacks. It would have been special.

15. Los Angeles Rams, 1968

The Rams fielded consistently great defensive lines from 1963 through the late 1970s. These lines were usually nicknamed the Fearsome Foursome, though the cast of characters changed from Rosey Grier, Deacon Jones, Merlin Olsen (shown) and Lamar Lundy in the early days to Olsen, Fred Dryer, Jack Youngblood and Larry Brooks at the end.

Grier and Lundy were gone in 1968. Dryer, Brooks, Youngblood and Coy Bacon (a star in the early 1970s) had not yet arrived. But this is a countdown of great defenses, not great defensive lines. The Fearsome Foursome may have been regrouping, but the rest of the Rams defense was in rare form.

All-Pro safety Eddie Meador intercepted six passes in 1968. Cornerback Clancy Williams added seven more. The linebacker corps featured Jack Pardee and Maxie Baughan. Jones and Olsen each earned All-Pro status, as the Rams recorded 51 sacks in 14 games to go with 25 interceptions. Opponents averaged just 3.3 yards per rush.

But this excellent Rams defense was stuck in the same league as other great defenses and teams. Year after year, the Rams either played second fiddle to the Colts in the NFL Coastal Division or slipped past them and into the path of the emerging Vikings.

In 1968, the Rams finished 10-3-1, but the Colts fielded an all-time great team and went 13-1. It was a familiar refrain for the Rams and a big reason why the Fearsome Foursome is more famous than the team they played for.

14. Baltimore Ravens, 2006

The Ravens didn't really field an exceptional defense and a mediocre offense every single year during the 2000s.

Sometimes they took the field with an excellent defense and a terrible offense. Or just a very good defense and an almost-passable offense.

Spoiler: There's a historic Ravens defense coming later in the countdown. This iteration of the Ray Lewis Ravens was nearly as good as the 2000 champions on defense and much better on offense, thanks to Steve McNair, Jamal Lewis and Derrick Mason.

Ray Lewis had one of his typical years (80 solo tackles, five sacks, two interceptions), while Bart Scott, Adalius Thomas and the young Terrell Suggs combined for 30 sacks. The secondary of Ed Reed, Chris McAlister, Samari Rolle and Dawan Landry combined for 19 of the Ravens' 28 interceptions. Opponents averaged just 75.9 rushing yards per game and scored just five rushing touchdowns.

The Ravens went 13-3 and hosted the Colts in the playoffs. They held Peyton Manning to 170 passing yards, no touchdowns and two interceptions. But McNair was also picked off twice, and the Colts won 15-6 on the strength of five Adam Vinatieri field goals.

A Ravens game turning into a messy field goal contest? You don't say. The 2006 team looked capable of doing much more. The defense certainly lived up to its end of the bargain.

13. Pittsburgh Steelers, 2008

James Harrison and LaMarr Woodley combined for 27.5 sacks, Troy Polamalu intercepted seven passes. Casey Hampton and Aaron Smith anchored a defensive line that plugged gaps and held opponents to 80.3 rushing yards per game and 3.3 yards per rush.

It may seem like the Steelers defense puts up numbers like that every year. But that's your imagination playing tricks on you. The Steelers maintain continuity so well that it is easy to forget that only Harrison remains from this Super Bowl-winning defense (Lawrence Timmons, another holdover, left in the offseason). The current Steelers are still good, but there is no Polamalu at strong safety or Hampton at the heart of the defense.

This defense held eight opponents to 10 points or less, a remarkable feat in the modern NFL. Opponents scored just 19 touchdowns against them during the regular season. Woodley and Harrison made their mark in a wild Super Bowl, Woodley with a pair of sacks, Harrison with one of the most memorable pick-sixes in football history.

For most other teams, a defense as good as the 2008 Steelers would stick out like a mountain in the franchise almanac. But all Steelers defenses stand in the shadow of the original Steel Curtain. And just as importantly, the Steelers are so consistently great on defense that seasons like these can almost look routine.

12. Miami Dolphins, 1973

Having gone undefeated and won the Super Bowl in 1972, the Dolphins returned for one of the least remembered great encores in NFL history.

While quarterback Bob Griese handed off and threw occasional bombs to Paul Warfield, the No-Name Defense recorded two shutouts and held five other opponents to a touchdown or less, including the Vikings in the Super Bowl. Safeties Jake Scott (shown, from Super Bowl VII) and Dick Anderson helped the Dolphins pass defense allow just five passing touchdowns while recording 21 interceptions and 45 sacks in a 14-game season. They did it all against a tougher schedule than the 1972 Dolphins faced.

But the 1973 Dolphins lost a pair of games, one to an excellent Raiders team, the other a 16-3 loss to the Colts in which Earl Morrall threw a pair of picks in relief of Griese. So the 1973 Dolphins are forever overshadowed by the 1972 team, which is no big deal because they were really the same bunch of guys.

The No-Name Defense also featured Hall of Famers Nick Buoniconti at middle linebacker and Bill Stanfill at defensive end. Top to bottom, it was a defense roughly on par with the Steel Curtain, Purple People Eaters and other better-branded units of the 1970s. Being remembered for going undefeated can mean that people forget the details. If going undefeated is the biggest challenge in football, repeating as Super Bowl champions is a close second. The 1973 Dolphins had a hand in both achievements. 

11. Green Bay Packers, 1962

The 1962 Packers defense allowed two touchdowns in its first four games. One of those touchdowns was a fourth-quarter pass to narrow the Packers' lead over the Vikings to 34-7.

In fact, four of the 14 offensive touchdowns the Packers allowed in 14 games came in the fourth quarters of blowouts, meaning that the team probably would have averaged under 10 points allowed per game if it had to really clamp down. As it is, they allowed an average of just 10.6 points.

The Packers defense allowed just 54 net yards in a 49-0 blowout of the Eagles. They forced seven turnovers, including four fumbles, in a 38-7 win over the Bears.

The Packers faced a star-studded Giants offense in the NFL Championship Game. Y.A. Tittle, Frank Gifford, Del Shofner and Co. never reached the end zone: The only Giants touchdown in the Packers' 16-7 win came on a fumble recovery in the end zone.

The names read like a Hall of Fame who's who: Ray Nitschke, Herb Adderley, Willie Wood, Willie Davis, Henry Jordan. The impact is felt beyond generations. If modern football begins when the AFL rises, the folks at NFL Films begin documenting every game like an epic battle and the Super Bowl becomes a gleam in the eyes of men like Pete Rozelle, then this is the first great defense in modern pro football history. Or perhaps this is the defense that helped usher in modern pro football history.

Either way, they were almost impossible to score on, even when you count the gimmies at the ends of blowouts.

10. Tampa Bay Buccaneers, 2002

If you close your eyes, you can still see exactly where every member of the 2002 Buccaneers "Tampa 2" defense lined up.

Warren Sapp: 3-technique, giving both a guard and tackle much to worry about. Booger McFarland: on the nose, clogging a primary artery. Simeon Rice: split too wide for any left tackle's comfort.

Derrick Brooks: on the weak side, in space, ready to flow to the running back or turn a quick slant into a big mistake. Shelton Quarles: undersized unsung hero of the whole system, a little farther back than the typical Mike linebacker, ready to pounce on an inside run or chase the tight end up the seam.

John Lynch and Dexter Jackson: usually twins at deep safety, with Lynch sliding down when coordinator Monte Kiffin wanted to stuff the run or rob an underneath zone. Ronde Barber and Brian Kelly: just outside their receivers, eyes in the backfield.

Kiffin ran the Tampa 2 defense in its purest distillation. Blitzes were rare. Deep safety support was a given on every play. It was a new kind of aggressive football: aggressively anticipating plays and jumping routes instead of unleashing easy-to-counterattack mayhem. It helped that Sapp and Rice provided all the mayhem a defense could ever want, no risky blitzing necessary.

The Buccaneers intercepted 31 regular-season passes and nine more in the postseason and Super Bowl, including five in the big game. This wasn't 1969, when quarterbacks threw two or three picks per game. This was the modern era of precision passing. Kiffin, taking over personnel and scheme from just-departed coach Tony Dungy, had simply devised a precision solution.

The Buccaneers held nine regular-season opponents and two playoff opponents to 10 points or less, then literally knew what the Raiders would do before they did it in the Super Bowl. They spawned lots of copycats. Fifteen years later, the Tampa 2 looks like a vanilla defense called when a team wants to bend without breaking. In 2002, it instilled a new kind of fear in offenses.

9. Detroit Lions, 1962

The Lions defense was teeming with Hall of Famers and superstars in 1962: Yale Lary (shown), Night Train Lane and Dick LeBeau in one of the greatest secondaries ever, Joe Schmidt at middle linebacker, perennial Pro Bowlers Alex Karras and Roger Brown on the defensive line. 

But the 1962 Lions shared the NFL's West Division with Vince Lombardi's Packers, Johnny Unitas' Colts and George Halas' last great Bears team. Also, their offense was terrible.

The Lions were undefeated when they faced the Packers in Green Bay in early October. They took a 7-6 lead late into the fourth quarter. But Milt Plum threw an interception to Herb Adderley, whose long return set up a game-winning Packers field goal by Paul Hornung.

That game sparked an offense vs. defense feud that would even make the current Seahawks feel awkward. The Lions still managed to win by 13-10, 11-3 and 12-3 scores, and they sacked Bart Starr 11 times in their Thanksgiving rematch with the Packers. But that was the only Packers loss of the season, while the Lions endured two other defeats by 17-14 (they held Y.A. Tittle's Giants to just 191 yards in the game) and 3-0 scores. There were no playoffs or wild cards back then. Second place in the division just meant a berth in the awful "Playoff Bowl," a consolation game detested by everyone.

The 1962 Lions tallied 57 sacks and 24 interceptions against a schedule full of Hall of Fame quarterbacks. They never trailed by more than seven points the entire season, a feat unmatched until the Packers did it in 2010. They may have been the greatest team to never make the playoffs. If their offense had just been decent, they would have been much more.

8. Seattle Seahawks, 2013

Super Bowl XLVIII started out with a safety, then got out of hand.

Peyton Manning and the Broncos, one of the greatest offenses in NFL history, ran seven plays for negative-three yards and two turnovers in the first quarter. The score was 22-0 at halftime, and the Seahawks offense hadn't done much: a couple of field-goal drives, a short touchdown set up by a Kam Chancellor interception. Manning made the stats look decent in the second half, but he couldn't do anything about the 43-8 final score, and we were finished writing our game stories in the third quarter anyway.

The Legion of Boom was dominant for the entire 2013 season. Richard Sherman, Earl Thomas, Brandon Browner and Chancellor led a secondary which recorded 28 interceptions. We've thrown a lot of huge interception totals around in this countdown, but intercepting 28 passes in 2013, when quarterbacks are super-precise and short-passing tactics hyper-efficient, is much harder than doing it in the up-for-grabs era of the late 1960s.

Opponents averaged just 8.9 yards per completion in 2013, another remarkable figure. The NFL's dedicated copycats took notice (as they always do), and every tall, physical cornerback to enter the draft for the last five years has been billed as a "Richard Sherman type."

The 2013 Seahawks defense has become a tone-setter for the modern NFL in the same way that the 1985 Bears (yes, they are coming) set the tone for the late 1980s. Like the Bears, the Legion of Boom can be brash, outspoken and perhaps a teensy bit arrogant at times. They talk the talk, but they walked the walk in Super Bowl XLVIII, and they may still have an encore in them.

7. Philadelphia Eagles, 1991

Randall Cunningham suffered an ACL tear in the first half of the first game of the season. Jim McMahon took his place and, being Jim McMahon, suffered a cascade of injuries that knocked him in and out of the lineup. The Eagles embarked on a strange journey through the wilds of third-string quarterbacking, with Brad Goebel, Pat Ryan and Jeff Kemp taking turns trying not to get mutilated behind a terrible offensive line.

Yet the Eagles remained in the playoff picture.

Buddy Ryan? He was long gone. These were Rich Kotite's Eagles, with legendary coordinator Bud Carson commanding the defense. Carson honed Ryan's marauders into a more professional operation, and the Eagles were able to win by 13-6 and 20-3 scores whenever McMahon was healthy enough to lift his arm.

Reggie White recorded 15 sacks. Clyde Simmons added 13, Jerome Brown nine. Eric Allen intercepted five passes. Seth Joyner was all over the field. The Eagles offense turned the ball over 43 times, but their defense recorded 48 takeaways. The Eagles averaged just 3.1 yards per rush, but opponents averaged just 3.0 yards per rush.

Along the way, the Eagles struck a death blow to the run 'n' shoot offense. Ryan may have called it the "chuck 'n' duck," but it was Carson's defense that forced six fumbles against the Oilers in the House of Pain Game, including the Warren Moon fumble shown above.

The 1991 Eagles defense may actually have been the best defense of all time. But there is only so much a defense can do when its offense scores 26 points and commits 18 turnovers in a four-game stretch. The Eagles won 10 games and stayed in the playoff chase until the final weeks of the season thanks to Carson, The Minister and Co.. It's almost as amazing an achievement as what the final defenses on our countdown accomplished.

6. New York Giants, 1986

You know the 1986 Giants by the trail of devastation in their wake, in the NFC East and the league at large.

Lawrence Taylor ended Joe Theismann's career in 1985. The Redskins turned to Jay Schroeder in 1986. The Giants intercepted Schroeder eight times and sacked him eight more times in two regular-season games, then held him to 20-of-50 passing in a 17-0 playoff shutout.

Ron Jaworski took such a pounding at the hands of the Giants in the mid-'80s that Buddy Ryan devised an insane two-platoon quarterback system in 1986: Jaws on early downs, elusive Randall Cunningham on third downs. The Giants sacked the two Eagles quarterbacks 13 times in 35-3 and 17-14 victories.

The Giants knocked Cowboys quarterback Danny White and backup Gary Hogeboom out of a late-season game in 1985. White got revenge in the 1986 season opener, but Carl Banks broke White's wrist in the first quarter of the rematch. New backup Steve Pelluer was sacked five times in a 17-14 loss. The Cowboys were 6-2 entering that game but finished the year 7-9. Banks' hit essentially ended the Tom Landry era.

The Cardinals were in the NFC East back then and fielded some solid teams behind quarterback Neil Lomax, a very good quarterback in his prime. Lomax endured 16 sacks in a pair of losses.

Having wrecked the NFC East, the Giants sought bigger prey. Joe Montana, like White, got the best of them in the regular season. Montana, like White, wouldn't make it to halftime in the rematch. Jim Burt knocked Montana out of the game (with Taylor returning Montana's errant throw for a touchdown), and the Giants stifled backup Jeff Kemp en route to a 49-3 divisional-round rout. Crushing the Broncos in the Super Bowl was a foregone conclusion.

Few defenses had more short-term and long-range impact than the 1986 Giants. Taylor's dominance forced opponents to deploy more two-tight-end sets, putting fullbacks on the road to extinction. The Cowboys were forced to reboot their franchise after two decades of sustained success. Cunningham's successes and failures framed the conversations about scrambling quarterbacks that still inform the way people talk about players like Cam Newton.

And of course, Bill Belichick was next to Bill Parcells on the sideline, orchestrating the chaos. But even Belichick would never again coach defensive personnel this great. His Patriots beat lots of opponents. The 1986 Giants often knocked them straight out of the NFL. 

5. Minnesota Vikings, 1969

The 1969 Vikings allowed 24 points in their season opener against the Giants and never allowed more than 14 points again until the first round of the playoffs.

Against a slate of quarterbacks that included Bart Starr, Fran Tarkenton (then leading the Giants), Roman Gabriel and Charley Johnson, the Vikings allowed just eight touchdown passes while racking up 30 interceptions.

The Purple People Eaters defensive line of Alan Page, Carl Eller, Jim Marshall and Gary Larsen all earned Pro Bowl berths while notching 49 sacks. Defensive backs Paul Krause, Bobby Bryant and Earsell Mackbee reaped the rewards of the ceaseless pass rush. On rare occasions when opponents scored a touchdown, the Purple People Eaters would erupt in laughter. As Marshall liked to say, the Vikings knew they were going to win the game anyway.

The 1969 Vikings were winners of the final NFL Championship Game, beating the Browns 27-7 on a typically Arctic afternoon at old Metropolitan Stadium. But the end of the 1960s was an era of legendary defenses, and in the last of the NFL-AFL Super Bowls, the Purple People Eaters met their match in the next team on our list.

4. Kansas City Chiefs, 1969

Everything about Hank Stram's 1960s Chiefs was innovative. On offense, they were among the first pro teams to deploy dozens of formations and regularly use rollout plays. In scouting, they combed small programs and historically black colleges when many organizations weren't far removed from picking players based on write-ups in Street & Smith magazines.

And on defense, Stram took all of those small-school finds and collegiate superstars the Chiefs acquired during the AFL-NFL war (Stram had a convincing sales pitch, owner Lamar Hunt a bottomless checkbook) and assembled them into the "Triple Stack" defense. Basically, it was an "over" formation that placed either Buck Buchanan or Curley Culp directly over the center, with middle linebacker Willie Lanier (shown) right behind the nose defender. But the defense could also look like a modern 3-4 alignment, making it a truly "multiple" front.

With talent like Buchanon, Culp, Lanier, Bobby Bell, Johnny Robinson and Emmitt Thomas, Stram could have tied everyone's shoelaces together and the Chiefs still would have won a lot of games. But when both Len Dawson and Jacky Lee got injured early in the 1969 season, Stram was forced to turn to third-stringer Mike Livingston at quarterback. The defense responded with 32 interceptions, 48 sacks and two shutouts.

When a still-gimpy Dawson struggled against Joe Namath's Jets in the playoffs, the defense preserved a 13-6 win with a late goal-line stand. And when the AFL champion Chiefs met the NFL champion Vikings in Super Bowl IV, the battle of defensive juggernauts was no contest. The Triple Stack defense overwhelmed the Vikings offensive line, while Stram's unpredictable offense confused the Purple People Eaters with short passes and unusual formations.

The 1969 Chiefs defense punctuated the end of a football era. The team's reign did not last very long. But its impact can still be seen and felt every Sunday.

3. Baltimore Ravens, 2000

You've probably been in a few sports arguments which took a turn for the Dilfer.

"My quarterback won more Super Bowls than yours, so my quarterback is better."

"You can't just go by Super Bowls. C'mon: TRENT DILFER WON A SUPER BOWL."

We've met our share of iffy quarterbacks on this list: Mark Sanchez, Brad Goebel, Milt Plum and others. But if the quarterbacks who were propped up by their defenses held a parade, Dilfer would be the Grand Marshall. That's not because he was the worst of these quarterbacks, but because he was the most obvious, successful beneficiary of a great defense. 

Ray Lewis and Rod Woodson were the cornerstones of the 2000 Ravens defense, but talent was everywhere. Chris McAlister and Duane Starks (10 combined interceptions) gave them a pair of shutdown cornerbacks. Peter Boulware, Rob Burnett and Michael McCrary (24 combined sacks) attacked from all angles. Sam Adams and Tony Siragusa kept blockers away from Lewis while anchoring the middle of the run defense and made everything else possible by holding opponents to 2.7 measly yards per rush. And the coaching staff was a who's who of contrasting styles and philosophies which somehow perfectly meshed: Marvin Lewis, Jack Del Rio, Rex Ryan, Mike Smith and others.

Tony Banks, not Dilfer, started the season at quarterback. The Ravens defense knew what was up. It recorded three shutouts in the first five weeks. When they allowed even one touchdown, bad things happened, as the Ravens lost three games by a combined 33-15 score.

Trent Dilfer rode to the rescue, providing just enough offense for the defense to do its job. By the playoffs, the Ravens perfected the formula: 21-3 over the Broncos, 24-10 over the Titans, 16-3 over the Raiders. Their 34-7 Super Bowl win over the Giants was a Ravens-style "offensive explosion:" interception return and kickoff return touchdowns, plus five turnovers to set up some short scoring drives.

The Ravens welcomed us to a new millennium by proving it was possible to win a Super Bowl with a bad quarterback.

Well, a kinda-OK quarterback, plus a historic defense.

Sports arguments have not been the same since. 

2. Pittsburgh Steelers, 1976

Steelers opponents called it a gimmick.

Mean Joe Greene lined up in a tilted stance between the center and guard instead of head-up on the guard. He shot the gap at the snap instead of reading keys and flowing to the ball.

Interior blockers were forced to converge on Greene, so speedy middle linebacker Jack Lambert was free to operate in space instead of tangling with centers and guards. On running plays, Lambert met the ball-carrier at or before the line of scrimmage. On passes, he often dropped into deep zone, safeties fanning out behind him, cornerbacks pummeling their receivers off the line.

Sure, it worked with players like Greene and Lambert, plus Jack Ham, Donnie Shell, Mel Blount, L.C. Greenwood and others. But there is no way such a hinky defense would survive the test of time, right?

Except that it did. The tilted tackle and 4-3 Stunt tactics that came with it became core concepts in modern one-gap defenses. The coverage scheme became the Cover 2 and the Tampa 2. Chuck Noll and Bud Carson's Steel Curtain taught the NFL how to play defense in an era when quarterbacks had gotten better, blockers more talented, receivers faster and systems more sophisticated.

The Steel Curtain blotted out the league for most of the 1970s, of course. The defense peaked in 1976 for the same reason great defenses so often peak: quarterback woes. Terry Bradshaw missed parts of six games, so backup Mike Kruczek came on to lead the team to 23-6, 27-0, 23-0, 32-16, 7-3 and 42-0 wins while usually throwing less than a dozen passes per game.

The final tally for the 1976 Steelers: five shutouts, three other games in which the opponent failed to score a touchdown. The beaten-up Steelers lost to the Raiders in the AFC Championship Game, but they had already won two Super Bowls and would win two more, so let's not quibble.

Sometimes a "gimmick" is really a breakthrough that's just waiting for the right time and the right people to make it a phenomenon. The '70s were the time, Greene, Lambert and Co. were the people, and the phenomenon is still going strong 40 years later.

1. Chicago Bears, 1985

The formula was simple.

Assemble the best defensive front seven the NFL has ever seen: Richard Dent, Dan Hampton, Mike Hartenstine/William Perry, Wilber Marshall, Steve McMichael, Otis Wilson and Mike Singletary.

Then attack relentlessly, unrepentantly, recklessly.

The 46 Defense, orchestrated by Buddy Ryan with the blessing of Mike Ditka, was distilled mayhem: a Viking raid on a coastal village, an onslaught that could sometimes be almost counterproductive. The Bears blitzed when there was no logical reason to blitz. Dent, McMichael and Hampton combined for 31.5 sacks by themselves. Wilson and Marshall's blitzing for 16.5 more was overkill. But Ryan sent Singletary and safeties, too, the attacks coming in waves.

A modern opponent might counterattack with spread formations and wide receiver screens. But this was the era when many coaches still stressed "establishing the run" and only a handful of teams were even deploying single-back sets. Establishing the run meant wasting downs, as the Bears allowed just 82.4 rushing yards per game and six rushing touchdowns. Quarterbacks who survived the blitz threw 34 interceptions: Safeties Gary Fencik and Dave Duerson and corners Leslie Frazier and Mike Richardson were capable, but they weren't required to do much more than fetch the cherries as they fell from the tree.

By the playoffs, the madness peaked. The Bears shut out two opponents before beating the Patriots, 46-10, recording 16 playoff sacks to go with 64 from the regular season.

The defense would reign for years afterward, but later opponents adapted, found weaknesses, attacked the Bears quarterbacks and waited for the Bears' aggression to turn on itself. Norse berserkers, after all, proved to be much better raiders than rulers. But even though they left devastation in their wake, they still made their mark all over the map. The Bears defense tore down the NFL's fortress in 1985. Thirty years later, we still marvel at the ruins.