The Hajj is associated with the life of Islamic prophet Muhammad from the 7th century AD, but the ritual of pilgrimage 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: each person walks counter-clockwise seven times around the Kaaba (a cube-shaped building and the direction of prayer for Muslims), trots (walks briskly) back and forth between the hills of Safa and Marwah seven times, then 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. After the sacrifice of an animal (can be accomplished by using a voucher (see below)), the Pilgrims then are required to either shave or trim their heads (male) or trim the ends of their hair (female). A celebration of the three-day global festival of Eid al-Adha proceeds thereafter.