Up next ... Wladimir Klitschko
The world heavyweight boxing champion reveals his journey from Soviet-era Kazakhstan to dominating the ring for the past decade along with his older brother Vitali. "We are very competitive. It's something that we have in our blood. We promised our mother not to fight each other," says the 39-year-old Ukrainian, who has 63 wins from 66 career pro fights. "My life motto is: Failure is not an option."