Even if you aren't a gymnastics fan, you've probably heard about the epic rivalry (and ultimately, friendship) between Shawn Johnson and Nastia Liukin. Although Johnson was a natural fit under the modern scoring system first implemented at the 2008 Olympic Games — in which a gymnast is scored on both difficulty and execution, with no maximum limit — the powerhouse was toppled by Liukin, whose grace and artistry proved that the sport had not changed as drastically as many believed.
Watch the pair's all-around showdown here.