Mixed martial arts has gained huge popularity over the last 15 years and the Ultimate Fighting Championship has become the front-runner of the sport's success.
In the early hours of Sunday morning, Great Britain's first UFC champion Michael Bisping makes the maiden defence of his middleweight title against long-time foe Dan Henderson at the Manchester Arena as part of UFC 204 - the 18th time the promotion has showcased an event in Britain.
Why is this fight significant?
There is no love lost between the fighters. This rematch has been brewing for seven years since their first bout in July 2009 at UFC 100 when Bisping was on the receiving end of a highlight-reel second-round knock-out. Henderson has since embedded a silhouette of the knock-out on to his fight shorts as a sweet reminder ahead of their long-awaited rematch.
What sort of crowd is expected?
Tickets for Bisping's homecoming sold out in six minutes with the Manchester Arena set to be packed to its full capacity of 21,000 in the early hours of Sunday morning.
How many people will watch worldwide?
At the conclusion of UFC 200, Forbes business magazine reported that the UFC reached up to 1.1 billion television households worldwide with events broadcast in up to 156 countries. Social media continues to be the driving force of MMA, with up to 3.3 million subscribers on the UFC's YouTube channel and 4.4 million followers on Twitter.
Is the UFC big business now?
The UFC began in 1993 with 36 American states banning the sport and the first event attracting 7,800 spectators. It grew under the ownership of Lorenzo and Frank Fertitta, alongside friend and UFC president Dana White, and the UFC now attracts sell-out crowds in 60,000-capacity arenas.
Now owned by WME-IMG, the company has still flourished: according to Fox Sports, Conor McGregor's rematch against Nate Diaz at UFC 202 broke the record for the total number of pay-per-view buys in the history of the sport with 1.65 million - which would rank eighth in boxing's most-watched pay-per-view fights.
What are the basic rules of the UFC?
The rules allow extreme violence although there are limits, such as no attacks on the groin area, no biting and regulations over attacks on the head. Fights take place in a fenced area normally called 'The Octagon'. All contestants are required to wear a mouthpiece during competition and male mixed martial artists must wear an approved groin protector.
All bouts are evaluated and scored by three judges on a 10-point system. A fight can end via unanimous, split, or majority decision, or in a draw. Submissions and technical knock-outs can also end a fight.
What is the format?
Championship fights, like the Bisping-Henderson clash, last a maximum of five rounds. Non-championship main events also last five rounds. Non-main event bouts last a maximum of three rounds. Each round lasts no more than five minutes, with a rest period of one minute between each round.