Situated in the holy city of Mecca by the Grand Mosque, the Kaa'ba is the house of God for Muslims. Meaning "cube" in Arabic, this is a shrine that predates Islam and where Muslims do the Hajj pilgrimage. It is believed to have been built by Abraham and when Angel Gabriel brought down the first part of the Qu'ran to Prophet Mohammed (Peace Be Upon Him) in 610, Muslims used to face Jerusalem when they prayed. But after the Prophet's decree, they face Mecca when they pray. It is believed that directly above the Kaa'ba in heaven is its replica and it's visited by angels.