The mausoleum of Husayn ibn Ali, grandson of the Prophet Muhammad, is the spiritual heart of the city and one of the holiest sites in Shi'a Islam. The golden dome and three minarets are visible from far across the flat plain, and the marble courtyard surrounding the shrine can hold tens of thousands of pilgrims. During the Arbaeen commemoration forty days after Ashura, the crowds become one of the largest annual gatherings of people on earth.
Non-Muslim visitors are generally not allowed inside the shrine itself, but the outer courtyard is usually accessible — dress conservatively, women must cover their hair, and cameras are restricted. The atmosphere is intense: prayers, weeping, the rhythmic chest-beating of mourners. Even visitors with no Shi'a connection find the experience unforgettable.