The Day of Arafah is considered one of the most important days, not only of the Hajj pilgrimage, but of the Islamic calendar.
Almost two million Muslims performing Hajj in Saudi Arabia have flocked into the valley of Mount Arafah to mark the most important day of the pilgrimage.
The 70-metre hill is where the Prophet Muhammad is believed to have given his final sermon about 1,400 years ago.
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Pilgrims spend the day praying at the site, and Muslims believe prayers in Arafah are answered and sins are cleansed.
Many Muslims who do not take part in the Hajj pilgrimage choose to mark the day by fasting and performing extra prayers.