Umayyad Mosque, Damascus.
Damascus is believed to be the oldest continuously inhabited city in the world and the Umayyad Mosque stands on a site that has been considered sacred ground for at least 3,000 years. The Umayyad Mosque, also known as the Grand Mosque of Damascus, is one of the largest and oldest mosques in the world, being completed in 715 AD. The spot where the mosque now stands was a temple of Hadad in the Aramean era. The site was later a temple of Jupiter in the Roman era, then a Christian church dedicated to John the Baptist in the Byzantine era, before finally becoming a mosque.
Credit: jemasmith / Flickr