UFC 13: Ultimate Force was a mixed martial arts event held by the Ultimate Fighting Championship on May 30, 1997 in Augusta, Georgia. The event was seen live on pay per view in the United States, and later released on home video.

UFC 13: The Ultimate Force

UFC 21: Return of the Champions was a mixed martial arts event held by the Ultimate Fighting Championship on July 16, 1999 at the Five Seasons Events Center in Cedar Rapids, Iowa. The event was seen live on pay per view in the United States, and later released on home video.