The pilgrimage to Karbala

Shiite pilgrims visit the holy city of Karbala, about 50 miles south of Baghdad. Streets leading into and out of Iraq’s capital have been choked by throngs of pilgrims. Thousands from throughout Iraq walk or drive to Karbala for the religious event despite the risk of violence. Attacks have occurred this year, and in past years Sunni Muslim insurgents have carried out assaults on Shiite pilgrims and religious sites. (Alaa al-Marjani / Associated Press)

Sept. 16, 2014 11:30 AM PT

Millions of Shiite pilgrims make the trip to Karbala, Iraq to mark Arbaeen, the end of a 40-day mourning period for Imam Hussein, the grandson of the Prophet Mohammed. Along the way scores, sometimes hundreds, die violently.

Shiite Muslim pilgrims flock toward the shrine of Imam Hussein in Karbala. (Mohammed Sawaf / AFP/Getty Images)

Shiite Muslim pilgrims pray at a holy shrine as hundreds of thousands arrive in the Iraqi city. (Mohammed Sawaf / AFP/Getty Images)

Shiite pilgrims reenact events that led to the death of revered Imam Hussein during a procession in Karbala. (Ahmed Alhussainey / Associated Press)

A pilgrim uses chains for self-flagellation, part of the ritual surrounding the religious commemoration. (Mohammed Sawaf / AFP/Getty Images)

Iraqi Shiite pilgrims march from Baghdad to Karbala past Iraqi soldiers. On Wednesday, attacks targeting the pilgrims rocked Baghdad, leaving 20 dead and more than 60 injured, government officials said. (Khalid Mohammed / Associated Press)

An Iraqi man clears debris following an explosion Thursday in Karbala. Eight pilgrims were killed in the bomb attack. (Mohammed Sawaf / AFP/Getty Images)