The occasion, known as the world’s largest annual Muslim pilgrimage. Arba’een, meaning “the fortieth” in Arabic, is observed 40 days after Ashura, the tenth day of the lunar calendar month of Muharram, when Imam Hussein, the grandson of Prophet Muhammad (PBUH), was martyred along with dozens of his companions at the hands of the tyrant of the time, Yazid . Shias, Sunnis, and people of other faiths from world countries have been on a spiritual sojourn to the Iraqi city — many from Iran and on foot — since almost three weeks ago. The martyrdom of Imam Hussein (AS) has turned into a symbol of righteous revolt and social and political reform. Imam Hussein (AS) is consequently a highly venerated figure not only among Shia Muslims but also among Sunnis and people of other faiths.
Starting since a few days before Arba’een, hundreds of different religious mourning processions, usually representing different communities and tribes of pilgrims from Iraq and around the world, passed by the golden domed shrines of Imam Hussein and his half brother Abbas ibn Ali (PBUH).
The pilgrims mourned and chanted slogans commemorating Imam Hussein's martyrdom along the way.
Due to the large amount of pilgrims present during the ceremonies, processions usually take several hours to enter and exit the areas adjacent to the shrines.
Many of the black-clad mourners have reached the city on foot to show their devotion to the Shia Imam.