Ever since the fall of Iraqi dictator Saddam Hussein in 2003, Shiites have begun once again openly marking the annual mourning holiday of Arbaeen, with the number of people taking part in the ceremony surging each year.
Arbaeen, described as the world's largest annual pilgrimage, is a ritual that occurs 40 days after the day the third Shiite Imam Hussein bin Ali was slain by forces loyal to the second Umayyad caliph Yazid in A.D. 680. Hussein, who was the grandson of Prophet Muhammad, is highly cherished and commemorated among Shiites for his battle against the thousands of troops dispatched by Yazid to confront him and his less than 100 companions.