The Hajj also referred to as the Hajj or the Greater Pilgrimage, is an annual Islamic pilgrimage to Mecca and the largest Muslim pilgrimage. It is one of the five pillars of Islam, a religious duty that must be carried out at least once in their lifetime by every able-bodied Muslim who can afford to do so. Hajj is also the largest annual gathering of people in the world. Hajj is performed from the 8th to 12th day of Dhu al-Hijjah, the last month of the Islamic calendar. Since 1994, Hajj has been expected to fall within September.