Alistair Overeem

Alistair 'The Reem' Overeem is one of combat sports' true crossover champions. He won the prestigious K-1 World Grand Prix in kickboxing while also holding heavyweight titles in Strikeforce and DREAM, a résumé few fighters in any era can match. He later challenged for the UFC heavyweight crown against the very best big men in the world.

In the cage, Overeem was an elite striker - punishing muay Thai knees in the clinch, heavy hands and crushing kicks. His offense could end anyone, as names like Fabricio Werdum and Mark Hunt found out. The flip side was a chin that became a target late in his career, which made his bouts thrilling: any Overeem fight could end in either direction.

Now retired, Overeem is remembered as one of the most accomplished and feared heavyweight strikers of his generation. For newcomers, he's a gateway to MMA's kickboxing-crossover history and a reminder that the heavyweight division's most exciting fights often hinge on a single punch.