Saudi Arabia started hosting the annual hajj pilgrimage on Sunday, with over 2 million Muslim faithful ready to take part in the ultraconservative kingdom. Since their arrival, many people have been seen circling the cube-shaped Kaaba in Mecca, Islam's holiest site. The Kaaba represents the metaphorical house of God and the oneness of God in Islam. Observant Muslims around the world face toward the Kaaba during their five daily prayers. The pilgrimage represents one of the five pillars of Islam and is required of all able-bodied Muslims once in their life.