The Hajj, also known as the Mecca Pilgrimage (var. Hadj), is an annual Islamic pilgrimage to Mecca, Saudi Arabia, the holiest city for Muslims. It is one of the five pillars of Islam, and is mandatory for all able-bodied Muslims who can afford it. The Hajj is a spiritual journey that involves several rituals, including circumambulating the Kaaba, praying at the Grand Mosque, and running between the hills of Safa and Marwa.