Alexei Navalny, a Russian opposition leader, walks out of a detention center in Moscow March 6, 2015. Navalny walked out of a Moscow detention center on March 6, a week after fellow opposition leader Boris Nemtsov was shot dead in what his allies say was a political killing aimed at intimidating them. REUTERS/Maxim Shemetov (RUSSIA - Tags: POLITICS CRIME LAW TPX IMAGES OF THE DAY)