Arbaeen comes 40 days after Ashura, the martyrdom anniversary of the third Shia Imam, Imam Hussein (AS).
Each year, a huge crowd of Shias flock to Karbala, where the holy shrine of Imam Hussein (AS) is located, to perform mourning rites.
A large number of children took part in the Arbaeen march this year, which concluded in mourning rituals on the day of Arbaeen on Thursday.