The hajj is the fifth of the fundamental Muslim practices and institutions known as the Five Pillars of Islam. The pilgrimage rite begins on the 7th day of Dhū al-Ḥijjah (the last month of the Islamic year) and ends on the 12th day.
The Haj ritual to Mecca is considered by Muslims to stretch back thousands of years to the time of Abraham. During Hajj, pilgrims join processions of millions of people, who simultaneously converge on Mecca for the week of the Hajj, and perform a series of rituals:
Runs back and forth between the hills of Safa and Marwah,
drinks from the Zamzam Well,
goes to the plains of Mount Arafat to stand in vigil,
spends a night in the plain of Muzdalifa,
and performs symbolic stoning of the devil by throwing stones at three pillars. The pilgrims then shave their heads, perform a ritual of animal sacrifice,
and celebrate the three-day global festival of Eid al-Adha.