Today, October 19, marks Arbaeen, which comes 40 days after Ashura, the martyrdom anniversary of the third Shia Imam, Imam Hussein (AS), and on which one of the largest religious gatherings in the world is held.
Each year, a huge crowd of Shias flock to Karbala, where the holy shrine of Imam Hussein (AS) is located, to perform mourning rites.
This year, over 3.5 million Iranians are among the pilgrims from around the world who have travelled to Karbala for Arbaeen.