Arbaeen is a significant observance in Iran and is considered one of the largest religious gatherings globally. The holiday marks the end of a 40-day mourning period following Ashura, the religious ritual that commemorates the death of Husayn ibn Ali, the grandson of Prophet Muhammad, in 680 AD. Arbaeen, which means 'forty' in Arabic, occurs on the 20th day of the month of Safar, the second month in the Islamic calendar. The holiday is marked by particular traditions and customs, many of which revolve around mourning and paying respect to Husayn ibn Ali.
During the Arbaeen commemoration, it is common for millions of Shi'ite Muslims to make a pilgrimage to the city of Karbala in Iraq, where Husayn ibn Ali's shrine is located. Iranians make up a large proportion of the pilgrims. Processions and mourning ceremonies are held, and the faithful participate in matam, a ritual of self-flagellation. Through these rituals, the participants express their sorrow and show their respect for the sacrifices made by Husayn ibn Ali.
Arbaeen in Iran is not only a religious event but also a day that gathers Iranians of all walks of life together, reinforcing their identity as the Shi'ite community. Despite its religious roots, the holiday has also become a significant cultural event and is seen as an opportunity for families to come together. The observance of Arbaeen is not an official public holiday in Iran, and businesses and faculties remain open. However, people usually take the day off voluntarily to attend the ceremonies and perform the rituals associated with the day.