Over the years, legitimate rivalries amongst fighters have brought UFC contests to bigger and bigger levels. From Tito Ortiz & Chuck Liddell to Conor McGregor and Nate Diaz, athletes with real world issues with one and other always garners attention like few other sporting contests.

In an episode of their 25 Years of the UFC documentary series, the UFC went back and revisited some of the sport’s biggest feuds, and the business behind them.