The UFC first premiered its reality competition series "The Ultimate Fighter" in 2005, and that inaugural season draws much credit for being the catalyst for the growth of the UFC and the sport of mixed martial arts.
The winner of each season earned a guaranteed six-figure contract with the UFC.
After a two-plus year hiatus, "TUF" will return with Season 29 in March 2021 and stream on ESPN+.
Here's a look at those mixed martial artists who won previous seasons of "The Ultimate Fighter" (U.S. editions only).
Season 1: Forrest Griffin, light heavyweight
The bout between Forrest Griffin, right, and Stephan Bonnar in the finale on April 9, 2005, is considered the greatest UFC fight ever. It was a three-round slugfest and is credited with launching the UFC into the mainstream. The bout was inducted into the UFC Hall of Fame.
Season 1: Diego Sanchez, middleweight
Often forgotten about as a debut season winner, thanks to the Forrest Griffin-Stephan Bonnar brawl, is Diego Sanchez. He beat Kenny Florian to win the contract on April 9, 2005.
Season 2: Rashad Evans, heavyweight
Rashad Evans won a split decision over Brad Imes to win the UFC contract on Nov. 5, 2005. He became one of the most successful "Ultimate Fighter" winners in UFC history, winning the light heavyweight title against Forrest Griffin.
Season 2: Joe Stevenson, welterweight
Joe Daddy Stevenson decisioned Nate Diaz, then decisioned New Hyde Park's Luke Cummo in the Ultimate Finale to win the contract on Nov. 5, 2005.
Season 3: Michael Bisping, light heavyweight
The first notable British import to the UFC, Bisping knocked out Josh Haynes in the second round to win the six-figure contract on June 24, 2006. Ten years later, he knocked out Luke Rockhold to win the middleweight title, making Bisping the fourth "TUF" winner to add a UFC title to his resume. At the time of his retirement in 2018, Bisping was the UFC leader in career fights at 29 and tied for the most wins at 20.
Season 3: Kendall Grove, middleweight
Kendall Grove won a unanimous decision over Ed Herman to get the UFC contract on June 24, 2006, and remained in the promotion for five-plus years and 12 fights.
Season 4: Matt Serra, welterweights
In the comeback season featuring UFC fighters who never won a title, East Meadow's Matt Serra decisioned Chris Lytle to earn a title shot against champion Georges St-Pierre on Nov. 11, 2006. Five months later, at UFC 69 in Houston, Serra became the only man in the world to knock out GSP and won the UFC welterweight championship.
Season 4: Travis Lutter, middleweight
Travis Lutter submitted Patrick Cote in the first round to win a title shot against champion Anderson Silva. He lost by second-round TKO.
Season 5: Nate Diaz, lightweight
Ever the tough guy with attitude, Nate Diaz submitted his way to the title, beating Manny Gamburyan on June 23, 2007, to win the UFC contract. He rose to prominence and the UFC and became a major star when accepted a fight on short notice against Conor McGregor and then submitted him in the second round at UFC 196 in March 2016.
Season 6: Mac Danzig, welterweight
Mac Danzig submitted all his opponents en route to winning the Ultimate Finale over Tommy Speer on Dec. 8, 2007.
Season 7: Amir Sadollah, middleweight
The widely popular Amir Sadollah submitted CB Dollaway to win the UFC contract and went 5-5 in the promotion.
Season 8: Efrain Escudero, lightweight
Efrain Escudero decisioned Brooklyn's Phillipe Nover on Dec. 13, 2008, to win the contract. Less than two years later, he was cut from the UFC after failing to make weight at Fight Night and going 2-2 since winning the TUF crown. He returned to the UFC twice more after that, going 2-5.
Season 8: Ryan Bader, light heavyweight
Ryan Bader knocked out Vinny Magalhaes in the Ultimate Finale to win the six-figure contract on Dec. 13, 2008. He worked his way into the upper tier of light heavyweights in the UFC, going 15-5 and fighting mostly every big name in the division. He later signed with Bellator and became that promotion's light heavyweight and heavyweight champion.
Season 9: Ross Pearson, lightweight
Team UK's Ross Pearson ran through the Americans during the preliminary bouts then won a unanimous decision over countryman Andre Winner to win the contract on June 20, 2009.
Season 9: James Wilks, welterweight
Team UK's James Wilks could be the only "TUF" guy to beat the same fighter twice in the same season. He then submitted Team USA's DaMarques Johnson to win the contract on June 20, 2009.
Season 10: Roy Nelson, heavyweight
Roy Nelson knocked out Brendan Schaub in the first round to win the title on Dec. 5, 2009. During the show, he stopped Kimbo Slice.
Season 11: Court McGee, middleweight
Court McGee, the former heroin addict who once was pronounced dead, defeated Kris McCray to win the title on June 19, 2010.
Season 12: Jonathan Brookins, lightweight
Jonathan Brookins won a unanimous decision over the favored Michael Johnson to win the six-figure contract on Dec. 4, 2010. He went 1-3 in the UFC after that.
Season 13: Tony Ferguson, lightweight
Tony Ferguson delivered a first-round knockout of Ramsey Nijem at the "Ultimate Finale" on June 4, 2011, to win a contract with the UFC. "El Cucuy" lost his first fight after that to Michael Johnson, then ripped off 12 wins in a row and became the No. 1 ranked lightweight and challenged for the interim title.
Season 14: John Dodson, bantamweight
John Dodson delivered a huge left hook -- no surprise there to viewers of Season 14 -- to knock out TJ Dillashaw to win the contract.
Season 14: Diego Brandao, featherweight
Diego Brandao used some impressive jiu-jitsu to turn an offensive onslaught from Long Island's Dennis Bermudez into an armbar submission to win Season 14. He went 5-4 in the UFC after that, with losses to Darren Elkins, Dustin Poirier, Conor McGregor and Brian Ortega.
Season 15: Michael Chiesa, lightweight
Michael Chiesa's father passed away from leukemia a few weeks into the filming of "TUF Live," and he still was able to fight his way to the final and win the UFC contract. He submitted Wantagh's Al Iaquinta to win the only live season on "TUF."
Season 16: Colton Smith, welterweight
Colton Smith, an active duty Army Ranger, won a unanimous decision over Mike Ricci to earn the Ultimate Fighter title. He lost all three of his fights by stoppage in the UFC after that, to Robert Whittaker, Michael Chiesa and Diego Ferreira.
Season 17: Kelvin Gastelum, middleweight
Kelvin Gastelum, 21, was the youngest TUF contestant in the show's history. He was also the last fighter picked by either coach. And then he ran through the competition and beat Uriah Hall by split decision in the final on April 13, 2013. He remains among the top ranked middleweights in the UFC, with wins over Johnny Hendricks, Michael Bisping and Jacare Souza on his resume.
Season 18: Julianna Pena, women's bantamweight
Julianna Pena advanced to the final of the first "TUF" season to feature female fighters by winning one decision and getting two stoppages. In the finale, she beat Jessica Rakoczy by TKO with one second left in the first round.
Season 18: Chris Holdsworth, bantamweight
Chris Holdsworth submitted Davey Grant in the second round to win Season 18 of "The Ultimate Fighter." He fought once after that, a win over Chico Camus, then took a break because of concussion issues and became a coach.
Season 19: Eddie Gordon, middleweight
Eddie Gordon, from Freeport, won three decisions to reach the finale, where he knocked out Dhiego Lima 71 seconds into the first round to win the middleweight division of the show on July 6, 2014.
Season 19: Corey Anderson, light heavyweight
Corey Anderson knocked out Matt Van Buren in the first round to win the light heavyweight division of the show on July 6, 2014.
Season 20, Carla Esparza, women's strawweight
In the first "TUF" season to feature all female fighters, Carla Esparza defeated Rose Namajunas in the final to win the season and be crowned the UFC's inaugural champion of the new 115-pound division on Dec. 12, 2014.
Season 22: Ryan Hall, lightweights
Ryan Hall lost in the semifinals on the show, but he returned in the final after Saul Rogers had visa issues and couldn't get back into the country for the finale. Hall dominated Artem Lobov with his jiu-jitsu to win a unanimous decision in 2015.
Season 23: Tatiana Suarez, women's strawweight
A bronze medalist in the 2008 and 2010 Wrestling World Championships, Tatiana Suarez defeated Amanda Cooper with a D'Arce choke at 3:43 of the first round in the finale.
Season 24: Tim Elliott, flyweight
Tim Elliott, the former Titan FC champion, won four fights to win the "TUF 24" season and earn a title shot against reigning UFC flyweight champion Demetrious Johnson. Elliott lost by unanimous decision to Johnson.
Season 25: Jesse Taylor, welterweight
It was billed as the show's "Redemption" season for past "TUF" participants. Jesse Taylor had reached the final in Season 7 but was removed from the fight after filming ending because of a incident in public. On TUF 25, the now-sober Taylor defeated Mehdi Baghdad, Hayder Hassan and James Krause to reach the welterweight final. He submitted Dhiego Lima in the second round at the finale to win the UFC contract on July 7, 2017.
Season 26: Nicco Montano, women's flyweight
This "TUF" season in 2017 featured female flyweight fighters, a new division for the UFC, with the winner of the show's finale becoming the promotion's 125-pound champion. Seeded 14th to begin the tournament, Montano won decisions over Lauren Murphy, Montana Stewart and Barb Honchak to reach the final. Montano then won a five-round unanimous decision over Roxanne Modafferi, who replaced Sijara Eubanks a day earlier, to earn the flyweight title on Dec. 1, 2017.
Season 27: Brad Katona, featherweight
This season featured fighters only with undefeated records coming into it. Katona kept his zero intact with wins over Kyler Phillips and Bryce Mitchell in the house, then a unanimous decision win over Jay Cucciniello in the featherweight finale on July 6, 2018.
Season 27: Michael Trizano, lightweight
Michael Trizano, from New Jersey, won a split decision over Joe Giannetti, on July 6, 2018, to win the lightweight bracket.
Season 28: Juan Espino, heavyweight
Juan Espino, at age 38, submitted Justin Frazier in the finale to win a UFC contract on Nov. 30, 2018.
Season 28: Macy Chiasson, women's featherweight
Macy Chiasson became the first "TUF" winner at women's featherweight when she submitted Pannie Kianzad in the finale.