Opposition politician and chairman of el-Ghad political party Ayman Nour speaks during a rally at Tahrir Square in downtown Cairo February 1, 2011. Hundreds of thousands of Egyptians, from students and doctors to the jobless poor, swamped Cairo on Tuesday in the biggest demonstration so far in an uprising against an increasingly isolated President Hosni Mubarak. REUTERS/Amr Abdallah Dalsh (EGYPT - Tags: POLITICS CIVIL UNREST)