Today, November 27th, marks the beginning of 2009's Eid al-Adha, the Muslim "Festival of Sacrifice", commemorating the willingness of Ibrahim (Abraham) to sacrifice his son to God. Muslims around the world will celebrate by slaughtering animals to commemorate God's gift of a ram to substitute for Abraham's son, distributing the meat amongst family, friends and the poor. Eid al-Adha also takes place immediately after the Hajj, a pilgrimage to Mecca that is a pillar of Islamic Faith. Some 2.5 million Muslim faithful from all over the world descended on Mecca this year, many encountering an unusual occurance: heavy flooding due to recent torrential rains. Collected below are photographs from this year's Hajj and observance of Eid al-Adha. ( 38 photos total