An aerial view taken on December 1, 2015 shows Iraqi Shiite pilgrims gathering at the shrines of Immam Abbas ibn Ali (front) and Imam Hussein (background) during the Arbaeen religious festival which marks the 40th day after Ashura, commemorating the seventh century killing of Prophet Mohammed's grandson, Imam Hussein, in the holy city of Karbala, 80 kilometres south of the capital Baghdad. AFP PHOTO / MOHAMMED SAWAF