Up to 2 million Muslims, from more than 70 countries, travel to perform the Hajj each year. The 9 mile journey is from the Mecca to the Plain of Arafat. Muslims gather for prayer and ceremonies at the holy sites of Mina and Muzdalifah. There are 2.4 million pilgrims who made the Hajj to Mecca last year, making it one of the largest human gatherings in history.