Vitaly Vladimirovich Klitschko ( Ukrainian: Віта́лій Володи́мирович Кличко́ [wiˈtɑl⁽ʲ⁾ij klɪtʃˈkɔ]; born 19 July 1971) is a Ukrainian politician and former professional boxer. He currently serves as Mayor of Kiev and head of the Kiev City State Administration, having held both offices since June 2014. Klitschko is a former leader of the Petro Poroshenko Bloc and a former Member of the Ukrainian Parliament. He became actively involved in Ukrainian politics in 2005 and combined this with his professional boxing career until his retirement from the sport in 2013. As a boxer, Klitschko is a three-time world heavyweight champion, the second-longest-reigning WBC heavyweight champion of all time, has the fifth-longest combined world championship reign in history at 2,735 days, the third-longest individual WBC heavyweight title streak of all time at 9 consecutive defenses, and the fourth-longest combined title streak in the modern heavyweight history at 15 title bouts. He held the WBO title from 1999 to 2000; the Ring magazine title from 2004 to 2005; and the WBC title twice between 2008 and 2013. Standing at 2.01 metres (6 feet 7 inches) and usually coming into fights around 250 pounds, Klitschko was renowned for having exceptional ring dominance. With an 87% knockout percentage, he holds the second highest knockout-to-fight ratios of any world champion in heavyweight boxing history, behind Rocky Marciano while also possessing a highly durable chin. He defeated seven world champions in the course of his career (Orlin Norris, Herbie Hide, Corrie Sanders, Samuel Peter, Juan Carlos Gómez, Shannon Briggs, and Tomasz Adamek), and was still the reigning WBC world heavyweight champion at 42 years of age when he finally announced his retirement in December 2013. His only two losses came via a shoulder injury and a deep cut above his eye, both of which were recorded as stoppages rather than outright knockouts; in both fights he was leading on the judges' scorecards. Klitschko is the only heavyweight boxer to have reigned as world champion in three different decades. Along with Oliver McCall and Nikolai Valuev, he is also the only world heavyweight champion to have never been knocked down in any fight. Klitschko and George Foreman are the only heavyweight boxers in history to defend a world title after turning 40. Being the first professional boxing world champion to hold a PhD degree, and in reference to his punching power, Klitschko's nickname was "Dr. Ironfist". His younger brother, Wladimir, is a former unified world heavyweight champion. From 2006 until 2015, Vitali and Wladimir dominated heavyweight boxing, a period typically known as the "Klitschko Era" of the division. Klitschko formally began his political career in 2006 when he placed second in the Kiev mayoral race. In 2010, he founded the party Ukrainian Democratic Alliance for Reform (UDAR) and was elected into parliament for this party in 2012. He was a leading figure in the 2013–2014 Euromaidan protests, and he announced his possible candidacy for the Ukrainian presidency but later withdrew and endorsed Petro Poroshenko. He was elected Mayor of Kiev on 25 May 2014. Klitschko headed the election list of the winner of the 2014 Ukrainian parliamentary election, the Petro Poroshenko Bloc, but he gave up his parliamentary seat to stay on as Mayor of Kiev. On 28 August 2015 the UDAR party merged into Petro Poroshenko Bloc. Klitschko thus became the new party leader. Klitschko was reelected as mayor on 15 November 2015. Klitschko revived UDAR, and left Petro Poroshenko Bloc with it, in May 2019 and simultaneously announced that UDAR would take part in the 2019 Ukrainian parliamentary election autonomously. UDAR however failed to win any seats.