Muslim pilgrims pray on a rocky hill called the Mountain of Mercy, on the Plain of Arafat, near the holy city of Mecca, Saudi Arabia, Wednesday, Sept. 23, 2015 during the hajj pilgrimage. Mount Arafat, marked by a white pillar, is where Islam's Prophet Muhammad is believed to have delivered his last sermon to tens of thousands of followers some 1,400 years ago, calling on Muslims to unite. (AP Photo/Mosa'ab Elshamy)