The hajj is a pilgrimage, or religious trip, that Muslims try to make at some point in their lives. The hajj is taken to the city of Mecca, the holiest site of Islam.
The hajj is one of the Pillars of Islam — acts that Muslims consider mandatory — which include faith, prayer, charity, and fasting. Unless they are financially or physically unable to make the trip, Muslims are expected to make the hajj at least once in their lives. The hajj is the world's biggest annual gathering, and it demonstrates Muslim faith and solidarity. The Arabic hajj comes from hajja, "he went on a pilgrimage."