Officials in Saudi Arabia say some two million Muslim pilgrims have made the journey for the Hajj, the annual pilgrimage to Mecca.
The Hajj is the oldest and most sacred ritual of Islam, required of all physically- and financially-able Muslims. Mecca is the birthplace of the Prophet Mohammed.
After morning prayers Sunday, the pilgrims moved from Mecca to Mina valley by road, train and on foot.
They will pray and rest in Mina before moving on Monday to Mount Arafat, where the prophet is said to have delivered his last sermon.
Saudi Arabia has deployed tens of thousands of troops to ensure the safety of the pilgrims.
The oil-rich kingdom has mobilized huge medical and civil defense resources to ensure the smooth movement of the pilgrims.
Coping with the world's largest annual human assembly has posed a security nightmare for Saudi Arabia. The oil-rich nation has invested billions of dollars over the years to avoid deadly stampedes that have marred the Hajj in the past. In July 1990, 1,426 pilgrims were trampled to death in a stampede.