18. Mike Tyson
Achievements as a Teen: In his first 15 fights at age 18, Iron Mike won all by either TKO or KO. We're really not too surprised. He made his pro debut on March 6, 1985 knocking out Hector Mercedes in the first round. Thus began the curious tale of one Mike Tyson, an oft-misunderstood figure that rose to boxing stardom.
Career Recap: After he threw his last punch, Tyson finished with a record of 50-6-0, racking up 44 KO's in the process. He is the former Undisputed Heavyweight Champion of the World, and holds the record as the youngest boxer to win the WBC, WBA, and IBF heavyweight titles. He was just 20 years old at the time. Mike has also provided us with numerous quotes, and plenty of laughs to last a lifetime. Salute to one of the truest, albeit controversial, American athletes and entertainers of our generation.