More than 1.1 million Muslims are expected in Saudi Arabia for the Hajj, the annual pilgrimage to Mecca, which begins next week.
All able-bodied Muslims who have the means have a duty to perform the Hajj, the fifth pillar of Islam.
Pilgrims wear special white clothes, called ihram, and observe prescribed rites derived from the life of Prophet Abraham.
Before the Hajj, many go to Jabal al-Nur, the Mountain of Light, at the top of which is the sacred Hira cave.
The prophet Muhammad is said to have received his first revelation from God through the Angel Gabriel in the cave.
Mecca is revered as the holiest site of Islam, and the Masjid al-Haram, or Holy Mosque, is the focal point of the Hajj.
Pilgrims pray at Mecca's Holy Mosque, and walk around the Kaaba seven times in an anti-clockwise direction to perform the Tawaf.