Shi'ite Houthi followers shout slogans as they attend a celebration marking Ashoura in Sanaa November 4, 2014. Ashoura, which falls on the 10th day of the Islamic month of Muharram, commemorates the death of Imam Hussein, grandson of Prophet Mohammad, who was killed in the seventh century battle of Kerbala. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS RELIGION)