Opposition leaders Boris Nemtsov (L, first row), Ilya Yashin (3d L, first row ), Garry Kasparov (C, second row) take part in the "March of Millions" protest rally in Moscow, September 15, 2012. Protesters chanting "Russia without Putin" began marching through Moscow on Saturday in a protest seen as a test of the opposition's ability to mount a sustained challenge to President Vladimir Putin. REUTERS/Mikhail Voskresensky (RUSSIA - Tags: POLITICS CIVIL UNREST)