Wladimir Klitschko is a Ukrainian former professional boxer who competed from 1996 to 2017. He held the world heavyweight championship twice, including the unified WBA, IBF, WBO, IBO, and Ring magazine titles. A strategic and intelligent boxer, Klitschko is considered to be one of the best heavyweight champions of all time. He was known for his exceptional knockout power, using a strong jab, straight right hand and left hook, quick hand speed, athleticism, as well as great footwork and mobility, unusual for boxers of his size. As an amateur, Klitschko represented Ukraine at the 1996 Olympics, winning a gold medal in the super-heavyweight division. After turning professional later that year, he defeated Chris Byrd in 2000 to win the WBO heavyweight title. Klitschko's first reign as champion ended in an upset knockout loss to Corrie Sanders in 2003, which was followed by another upset knockout loss to Lamon Brewster in 2004.