Millions of mourners across the world are preparing to mark the occasion by holding mourning rituals on Wednesday. Millions of Iranians have also traveled to Iraq to take part in Arba'een march and attend mourning ceremonies in Karbala.

Imam Hussein and 72 of his loyal companions, including family members, were martyred on Ashura, the tenth day of the lunar month of Muharram, in the battle of Karbala against the second Umayyad caliph, Yazid I, in 680 A.D. Imam Hussein was martyred after he refused to pledge allegiance to the tyrant ruler.