Braving intense heat, sand storms, and precarious security situation, millions of Shia Muslims from different corners of the world converge at one place and cover vast swathes of land by foot.

This annual event that has become a talking point in recent years is known as Arbaeen march, which takes place 40 days after Ashura, the day famous for the tragic event of Karbala, when Hussain, the grandson of Islam’s Prophet, was killed on October 10, 680.

Read more: Millions march to Iraq for Arbaeen pilgrimage