More than 2 million Muslims have begun the annual hajj pilgrimage. The five-day pilgrimage represents one of the five pillars of Islam and is required of all able-bodied Muslims once in their life.

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Muslim pilgrims attend noon prayers on the road near the Namirah mosque on Arafat Mountain, during the annual hajj pilgrimage, outside the holy city of Mecca, Saudi Arabia, Monday, Aug. 20, 2018.

(Pictures: AP/Dar Yasin).

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Muslim pilgrims leave after offering noon prayers on the road near the Namirah mosque on Arafat Mountain.

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Muslim pilgrims walk towards Namirah mosque on Arafat Mountain, during the annual hajj pilgrimage, outside the holy city of Mecca, Saudi Arabia, Sunday, Aug. 19, 2018

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In this Aug. 16, 2018, photo taken with a long exposure, Muslim pilgrims circle the Kaaba as they pray at the Grand Mosque, ahead of the annual Hajj pilgrimage in the Muslim holy city of Mecca, Saudi Arabia. 

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Muslim pilgrims leave Grand Mosque, after offering Friday prayers ahead of the annual Hajj pilgrimage, in the Muslim holy city of Mecca, Saudi Arabia

(All Pictures: AP Photo/Dar Yasin).