Photo and caption by Christopher Leslie

Shia pilgrims, taking part in Arbaeen, walk to Karbala under the gaze of guards and Iraqi security forces near a U.S. military base in central Iraq in February 2010. Arbaeen is the Shia Muslim commemoration of the martyrdom of Husayn bin Ali, the grandson of the Prophet Muhammad. Despite the ever-present threat of violence in Iraq - indeed, more than 100 pilgrims were killed in separate bombings - more than 10,000,000 pilgrims from all over the world took part in Arbaeen in 2010.

Location: Babil Province, Iraq