Egyptian protesters walk away after riot police used tear gas during a protest in Tahrir Square to call for the fall of Islamist President on January 24, 2012 in Cairo. Police clashed with protesters in Cairo earlier, on the eve of the the second anniversary of the uprising that overthrew Hosni Mubarak, as they tried to dismantle a security barrier and called for the fall of President Mohamed Morsi. TOPSHOTS/AFP PHOTO/MOHAMMED ABED