Arbaeen, which is one of the largest religious gatherings in the world, comes 40 days after Ashura, the martyrdom anniversary of the third Shia Imam (AS).

This year it falls on Thursday, October 8. Mourning rituals are held every night in the holy cities, especially at the holy shrines of Imam Hussain (AS) and Hazrat Abbas (AS).

Source: en.shafaqna.com