It's where greatness is defined, will is tested, and limits transcended. We find proving grounds in Dallas, Texas, where Australian superhuman Liz Cambage is exploding stereotypes of WNBA athletes. We discover them in the dark waters of the Everglades, where a nocturnal scene of "herpers" hunt for reptiles for bounty and glory. Elsewhere in Florida, brotherhood is tested as sibling kickers vie for supremacy and sanity in an elite football family. In Ohio, proving grounds are on the mat, where wunderkind heavyweight Kyle Snyder is putting Olympic wrestling back on America's radar. And, in a look back at legendary athletes who retired at the top of their game, we test the outer limits with a question: Where do you go when you have nothing left to prove?