Several million Shia pilgrims have been marking the religious festival of Arbaeen, in the Iraqi city of Karbala. BBC reporter Jaafar Nasrawi is in Karbala and has sent these pictures.
Arbaeen marks the end of a 40-day mourning period for the death of Imam Hussein, grandson of the Prophet Muhammad, in 680 AD.
The martyrdom of Imam Hussein was a key event in the schism between Sunnis and Shias in Islam.
For nearly 30 years under the regime of Saddam Hussein, who was a Sunni Muslim and drew much of his power from Sunni tribes, it was forbidden to mark Arbaeen publicly in Iraq.
Many pilgrims travel miles on foot to reach Karbala. Men and women walk separately.
Many people wear the traditional ceremonial colours of black and green.
Shias mark the event around the world. Hasnain, in London, emailed the BBC to say Arbaeen "teaches us about the meaning of sacrifice and to stand up against injustice and oppression".