A woman climbs toward the top of Noor Mountain ahead of the annual hajj pilgrimage in the holy city of Mecca, Saudi Arabia on Sept. 7, 2016. The Quran holds that the Prophet Muhammad heard his first revelation from God while atop Noor Mountain.
Muslim pilgrims visit the Hiraa cave at the top of Noor Mountain on Sept. 7.
The cave is believed to be where the prophet prayed and received the divine inspiration to preach and spread Islam.
Pilgrims pray at Noor Mountain on Sept. 7.
Children from Mecca play on top of Noor Mountain on Sept. 9.
A woman prays on Noor Mountain on Sept. 7.
A man prays on Noor Mountain on Sept. 7.
A pilgrim prays at Noor Mountain on Sept. 7.
Muslim pilgrims circle the Kaaba at the Grand Mosque in Mecca on Sept. 6.
Islam's 1.6 billion followers pray toward the cube-shaped shrine five times a day.
A pilgrim sleeps while reading the Koran at the Grand Mosque on Sept. 8. The hajj pilgrimage is an act of faith required of all able-bodied Muslims once in their life.