Remember when Randy Couture came out of retirement and dominated Tim Sylvia? How about when Quinton Jackson shocked the world by knocking out Chuck Liddell in the first round? Or, when Georges St-Pierre captured his first welterweight championship by beating Matt Hughes in a rematch?
All of MMA's greatest fighters have career defining moments; instances that encapsulate them as a fighter, or that they will always be most remembered for.
These moments are inherently important. Some of them are significant solely because they'll help us to always remember the greats of the sport, but many of them have actually helped to shape the sport of mixed martial arts and bring it into the mainstream.
Today we take a walk down memory lane, examining the 75 greatest fighters in MMA history and the moments that defined their careers...