Muslim pilgrims wait for the start of prayers at the Grand Mosque in the Saudi holy city of Mecca. – Photo by AFP

Muslim pilgrims are descending in droves on Mecca for the hajj pilgrimage, the world's largest annual gathering which Saudi Arabia insists will not be affected by instability rocking the region. – Photo by AFP

Pilgrims perform their prayers in the Grand Mosque of the holy city of Mecca. – Photo by AFP

Pilgrims circle the Kaaba and pray at the Grand mosque. – Photo by Reuters

Pilgrims attend a prayer session along a street. – Photo by Reuters

Pilgrims circle the Kaaba. – Photo by Reuters

Muslims circle the Kaaba. – Photo by Reuters

Muslims circle the Kaaba and pray at the Grand mosque during the annual haj pilgrimage. – Photo by Reuters

The sun sets over the holy city of Mecca as seen from the top of Mount Noor. – Photo by Reuters

Muslims pray at the top of Mount Noor. – Photo by Reuters

A Muslim prays at Jabal al-Noor 'mountain of light.' – Photo by AFP

A pilgrim makes his way out of the Hera cave on Mount Noor. – Photo by Reuters

View from the top of Noor Mountain. – Photo by AP