The Umayyad Mosque, also known as the Great Mosque of Damascus located in the old city of Damascus, is one of the largest and oldest mosques in the world. It is considered by some Muslims to be the fourth-holiest place in Islam.
After the Arab conquest of Damascus in 634, the mosque was built on the site of a Christian basilica dedicated to John the Baptist (Yahya). The mosque holds a shrine which today may still contain the head of John the Baptist, honored as a prophet by both Christians and Muslims alike, and is believed to be the place where Isa (Jesus) will return at the End of Days. The tomb of Saladin stands in a small garden adjoining the north wall of the mosque.