The Chicago Bears have been in existence since 1922. There have been countless legends to pass through Chicago. Ever since the George Halas days, the Bears have been strong in the drafts and in free agency.

Chicago has had some down years as of late. They have been in the playoffs just once since 2011. Their quarterback situation is questionable and they have many holes to fill. The defense is still strong and that's how it has been throughout history. Many of their top free-agent signings have been on the defensive side. Here are the best free-agent signings in team history.

5. Thomas Jones

Jones was taken seventh overall by the Arizona Cardinals in 2000. He never lived up to the hype and needed a change of scenery. The Bears signed Jones to a four-year, $10 million deal in 2004. Jones made an impact immediately as a dual-threat back. He rushed for 948 yards and seven touchdowns in 2004 while catching 56 passes.

The most productive year for Jones in Chicago came in 2005 when he ran for 1,335 yards and nine touchdowns. His tenure was cut short when Chicago traded him to the New York Jets after Jones did not participate in the team's voluntary offseason program in 2006. That paired with the Bears drafting Cedric Benson led to Jones' end. For three years, the Bears had a steady run game to pair with a strong defense.

4. Julius Peppers

The Bears made a huge splash in 2010 by signing Peppers to a six-year, $84 million deal. The All-Pro defensive end came in and did not miss a beat with Chicago. He put up eight sacks, two interceptions, 11 tackles for loss, and 18 quarterback hits. Peppers was named to the Pro Bowl and First Team All-Pro.

Peppers' sack numbers went up over the next two seasons topping out at 11.5 in 2012. He was a Pro-Bowler during his first three seasons in Chicago. Peppers gave the Bears a dominant pass-rusher—something for which the franchise is known. He spent four seasons in Chicago before being released and signing with the Green Bay Packers.

3. Tim Jennings

Jennings was a second-round pick of the Indianapolis Colts in 2006, but he is known for his time in Chicago. In 2012, Jennings turned into one of the top corners in the game. He finished with a league-leading nine interceptions. He was named to the All-Pro Second Team.

Jennings will go down as one of the top cornerbacks in franchise history. He ended his five-year tenure with 16 interceptions, 257 return yards, and three touchdowns. The Bears released Jennings before the 2015 season.

2. Gary Fencik

Fencik only played for the Bears, but he was not drafted by the team. In 1976, Fencik was a 10th-round pick of the Miami Dolphins but was released after suffering a ruptured lung in the preseason. The Bears quickly scooped up the safety and it worked out big time.

Fencik was a staple for the Bears for 12 years. He started all 16 games for the 1985 Bears, which was the best defense in the history of the NFL. Fencik ended his career with 38 interceptions, 488 return yards, one touchdown, and 13 fumble recoveries.

1. Steve McMichael

McMichael spent 13 years in Chicago after signing in 1981. He was a huge part of the 1985 team along with Fencik. The ability to stay on the field is something that can take a player's legacy to the next level. McMichael played 191 straight games as a Bear and made 157 starts.

The list of accomplishments for McMichael is endless. He was a two-time Pro-Bowler, two-time first-team All-Pro selection, and three-time All-Pro Second Team member. McMichael finished his Bears' career with 92.5 sacks, 16 fumble recoveries, 12 forced fumbles, and two interceptions. McMichael is highly regarded as one of the best players in franchise history.