Record numbers endure economic strain and heat for annual Hajj pilgrimage in Mecca.

More than two million worshippers from over 160 countries are expected to attend the Haj pilgrimage in Makkah, Saudi Arabia, making it one of the world's largest annual religious gatherings. The Haj is one of the five pillars of Islam and must be undertaken by all Muslims with the means at least once in their lives. The rituals include circling the Kaaba, praying on Mount Arafat, and "stoning the devil" by throwing pebbles at three giant concrete walls representing Satan. The Haj generates an estimated $12 billion annually for Saudi Arabia, which is embarking on an ambitious plan to overhaul its largely oil-dependent economy.