Ravens defenses have been in rare company over the last few years.
Baltimore's defense finished this season as the league's No. 7 overall unit, allowing an average of 322.1 yards per game. It's the third straight year the Ravens have finished a season ranked in the top 10* *in overall defense.
The only other teams in the league who have also accomplished that feat are the Denver Broncos and Seattle Seahawks. The Broncos and Seahawks have both won a Super Bowl during that time, largely because of the play of their defenses.
"We came a long way with our defense in the last two years," Head Coach John Harbaugh said during his season-review press conference earlier this month.
"I think we built one of the best defenses in the National Football League. Certainly, it showed through the first 12 weeks of the season and, really, the last eight weeks of [the 2015] season. We revamped our defense dramatically over the offseason last year. I'm really proud of what we did."
The Ravens ranked in the top five in total defense for most of the season, and spent a portion of the year at the top of the league. The unit fell back in the last month of the season, particularly because of tough games against the New England Patriots and Pittsburgh Steelers.
In that final stretch, the Ravens struggled to stop the run the way they had earlier in the year, and premier quarterbacks like Tom Brady and Ben Roethlisberger also had their way against a secondary playing without top cornerback Jimmy Smith.
"We didn't play nearly as well the last four [games]as we did the first 12," Harbaugh said. "What we didn't do at the end was we didn't make the plays that we made early in the season on the back end."
Despite the way the season ended, the Ravens defense still has plenty of upside going into next year. Linebacker C.J. Mosley is a rising star, safety Eric Weddle is a difference maker in the secondary and outside linebacker Terrell Suggs can still affect games in many ways.
The Ravens also have Dean Pees returning for his sixth season as the team's defensive coordinator.
"I think Dean did a great job with it. Our coaches did a great job, and our players," Harbaugh said. "We were the best defense in the league for 12 weeks, statistically. We were toward the bottom the last four weeks. That's exactly the question we have to look at. We've looked at it really specifically, so that's a general overview of it – what it is going to take to be the best defense in the league for 16 weeks-plus."