The hajj, or pilgrimage to Mecca, is very significant to Islam. Indeed it is one of the "five pillars" of the faith, along with the belief in Allah and Muhammad his prophet, prayer five times a day, alms, and fasting during the holy month of Ramadan. The pilgrimage is to the Kaaba, or House of God, which was built by Ibrihim and Ishmael at the command of Allah. Located there is a black stone known as Al-Hajar Al-Aswad, given to Ibrihim by the Archangel Gabriel. Ibrihim returned to the site each year. After a long period of control by other peoples, the Prophet Muhammad, following his journey from Medinah to Mecca in 630 restored the Kaaba, dedicating it exclusively to Allah. The process of hajj itself involves a great deal of carefully observed rituals and rites, and is both an expression of faith and submission to Allah and of unity with followers of Islam around the world.