In the late-1980s, a VHS tape circulated through the martial arts underground. The grainy video, Gracies in Action , showed a slim Brazilian fighter in a traditional gi fighting a boxer, a wrestler, and finally a karate master. Art Davie saw the tape, and with Rorion Gracie, devised War of the Worlds , a combat tournament featuring fighters from every discipline. In 1993, the Ultimate Fighting Championship debuted in Denver, Colorado, and 86,000 home...