The Hajj pilgrimage draws millions of Muslims from around the world every year to Mecca, the birthplace of the Prophet Muhammad, Islam's holiest place. Saudi Arabia expects to host perhaps three million people in a ritual journey that every able-bodied Muslim who can afford it must make at least once in their lifetime. It is the largest annual gathering of humanity anywhere. Timed to the Muslim lunar calendar, the Hajj is followed by the celebrations of the three-day festival of Eid al-Adha, or the Feast of Sacrifice, which symbolizes Abraham's willingness to sacrifice his son. Collected here are photographs of the Hajj in Mecca, Saudi Arabia, as well as images of preparations for the Hajj and Eid al-Adha in many other parts of the Muslim world. -- Lane Turner ( 42 photos total