It is a sacred duty for Muslims, wherever they may reside, to go at least once in their lives to Mecca, the heartland of Islam where the Prophet Muhammad received the revelation in the early 7th century. Drawing millions of pilgrims annually, the Hajj is a powerful bond that brings Muslims together from across the world. It takes place in the twelfth month of the Muslim year dhu’l hijja. Over the course of one week a number of specific rituals are performed which involve circumlocution of the Ka’ba, the cube-shaped building in the centre of the sanctuary at Mecca, and visiting key sites.