UFC 36: Worlds Collide was a mixed martial arts event held by the Ultimate Fighting Championship at the MGM Grand Arena on the Las Vegas Strip in Paradise, Nevada on March 22, 2002. The event was seen live on pay per view in the United States, and later released on home video.

The card was headlined by two Title Bouts, a Heavyweight Championship bout between Randy Couture and Josh Barnett and a Welterweight Title Bout between Matt Hughes and Hayato Sakurai. UFC 36 marked the last UFC appearance of former 170 lb Champion Pat Miletich, and the last appearance of Pete Williams. Miletich decided to concentrate on training his fighters, including Matt Hughes who was now the UFC champion in Pat's preferred weight class.

Hughes was originally supposed to fight (at the time) Shooto welterweight champion, and future UFC middleweight champion Anderson Silva. However, Silva had signed a contract with PRIDE Fighting Championships.

Barnett defeated Couture via TKO (strikes) at 4:32 of the second round to become the new UFC Heavyweight Champion. Afterwards, Barnett was stripped of the title when he tested positive for steroids during a mandatory post-fight drug test.

Fedor Vladimirovich Emelianenko (Russian: Фёдор Влади́мирович Емелья́ненко, tr. Fyodor Vladimirovich Yemelyanenko, IPA: [ˈfʲɵdər vlɐˈdʲimʲɪrəvʲɪtɕ jɪmʲɪlʲˈjanʲɪnkə]) (born September 28, 1976) is a Russian heavyweight mixed martial artist. He has won numerous tournaments and accolades in multiple sports, most notably the Pride 2004 Grand Prix and the World Combat Sambo championship on four occasions, as well as medaling in the Russian national Judo championship.

Emelianenko has received widespread acclaim from several major publications, including Sports Illustrated,USA Today, and Sherdog.com. Many analysts, as well as former and current fighters, consider Emelianenko to be the greatest mixed martial artist of all time. He remained undefeated for nearly a decade, during which time he was widely considered the best heavyweight fighter in mixed martial arts.

Emelianenko was born in 1976 in the city of Rubizhne, Luhansk Oblast, Ukraine (then in the USSR). In 1978, when he was two, his family moved within the Soviet Union to Stary Oskol, Belgorod of the Russian SFSR. His mother, Olga Fedorovna, was a teacher and his father, Vladimir Alexandrovich Emelianenko, was a welder. Emelianenko is the second child in the family and has an older sister and two younger brothers, including professional mixed martial artist Alexander Emelianenko. Fedor trains with his youngest brother Ivan, who has competed in Combat Sambo, and plans to begin a career in MMA in 2010.

Timothy Deane Sylvia (born March 5, 1976) is an American professional mixed martial arts (MMA) fighter, professional wrestler, and former two-time UFC Heavyweight Champion. He trains as a member of the Miletich Fighting Systems camp and is part of the Miletich Fighting System Elite group which has had members such as former UFC champions Matt Hughes and, Jens Pulver. Sylvia was promoted to a purple belt in Brazilian Jiu-Jitsu on October 31, 2011. He holds notable wins over Andrei Arlovski (x2), Jeff Monson, Ricco Rodriguez, Paul Buentello, Brandon Vera, Jason Lambert and Ben Rothwell

Sylvia joined a karate school as a child, and began wrestling in high school. After graduation, he worked construction, community gardening, hanging sheet rock, a bouncer for Shane Reids bar, and painting houses. He was playing semi-pro football when he became interested in MMA, and began to train with Marcus Davis. During this time he decided to take up boxing and grappling. After training for a year, he got the opportunity to fight in a Rhode Island no-holds-barred amateur event, in which he knocked out his opponent in 17 seconds.

Erick Silva (born June 21, 1984) is a Brazilian professional mixed martial artist who competes in the welterweight division. A professional MMA competitor since 2005, Silva has spent the majority of his career in Brazil, mostly notably for Jungle Fight where he was the inaugural Welterweight champion.

Silva comes from Vila Velha, Brazil and was an X-Gym training partner for the likes of Anderson Silva, Rafael Feijao and Jacare Souza. He also trains with Team Nogueira and Pro Fight.

Silva joined Jungle Fight, appearing at Jungle Fight 9 against Carlos Eduardo dos Santos. In the third and final round, Silva defeated dos Santos via rear naked choke.

At Jungle Fight 11, he defeated Igor Fernandes via unanimous decision. Silva followed that up with two further victories in the promotion.

Silva then competed in one of the more unique fights in his career, at Jungle Fight 17, which was held outdoors. On the day of the event, the weather was clear throughout, until less than an hour before the start, when rain began to fall and never stopped. The event, which went down as one of the wettest in MMA history was not a successful one for Silva who hit his downed opponent with a knee, resulting in a no contest verdict.

Geghard Movsesian (Armenian: Գեղարդ Մովսեսյան, August 1, 1985 - ), better known as Gegard Mousasi, is an Armenian mixed martial artist and kickboxer. He is fighting out of Team Jurojin in Leiden, Netherlands and is a member of Russian Red Devil Sport Club and Netherlands' Golden Glory. He is the current Dream Light Heavyweight champion, former Dream Middleweight Champion, Cage Warriors Middleweight Champion and the former Strikeforce Light Heavyweight Champion. Mousasi is currently ranked as the #8 light heavyweight fighter in the world by MMAWeekly.

In February 2010, Mousasi left M-1 Global Management. Mousasi was quoted as saying "After careful consideration, I have decided that it is in my best interest to part ways with M-1 Global," Mousasi wrote in the e-mail. "During the time I spent under their wing, M-1 Global, as a promoter and management company, allowed me to achieve many great things. I appreciate all they have done for me. My management is being taken care of by someone close to me."