Hundreds of thousands of Muslims have begun arriving in Saudi Arabia for the upcoming annual hajj amid the blistering heat and rising political and military tensions in the region.
This year's hajj is expected to feature large numbers of pilgrims from Iran, whose government had boycotted the event after an estimated 2,300 pilgrims, many of them Iranians, were crushed to death in a ritual near Mecca in 2015.
The hajj this year will run from August 19 to August 24 and is expected to draw 2 million of the world's estimated 2 billion Muslims.
Every Muslim is required to complete the hajj -- considered one of the five pillars of Islam -- at least once in their lifetime if they have the means to do so.
Muslims around the world pray toward the Kaaba, which is located in the Grand Mosque in Mecca, and pilgrims walk around it seven times.
The Saudis stake their reputation on the guardianship of Islam's holiest sites and the conducting of a peaceful hajj.
Besides the 2015 tragedy, the event has been marred in the past by deadly fires and riots.