Reuters Pictures
Students burn pictures of U.S. President Barack Obama shaking hands with former Israeli Prime Minister Ehud Olmert, in front of the former U.S. embassy during a gathering to mark the anniversary of freezing Iran and US diplomatic ties in Tehran April 9, 2009. The United States cut off diplomatic ties with Tehran during the 1979-1981 hostage crisis in which a group of militant Iranian students held 52 U.S. diplomats hostage at the American Embassy for 444 days.