Supporters of the head of radical leftist Syriza party Alexis Tsipras celebrate on a street after their leader won the election in Athens January 25, 2015. Tsipras promised on Sunday that five years of austerity, "humiliation and suffering" imposed by international creditors were over after his Syriza party swept to victory in a snap election on Sunday. REUTERS/Marko Djurica (GREECE - Tags: POLITICS ELECTIONS)