A 400-pound wall of pure muscle wrapped in a surprisingly gentle soul—until you threaten its family. The silverback gorilla can bench-press an estimated 1,800 pounds and possesses grip strength capable of crushing a crocodile's skull with its bare hands. Pound for pound one of the strongest animals on Earth, and smart enough to learn sign language while doing it.

Iron Mike Tyson became the youngest heavyweight champion in history at age 20 and terrorized the boxing world with concussive power that bordered on illegal. His peek-a-boo style and devastating uppercuts ended 44 fights by knockout, often in the first round. Opponents didn't just lose to Tyson—many admitted they were beaten before the bell even rang.