The Aya Sofya is a giant mosque that was built in 527-65 AD by a Christian Emperor. Originally it was a cathedral. After the Conquest of Constantinople in 1453 when it was converted into the mosque. The most amazing part of the building is the giant dome which was built with no apparent support. There are also large golden-textiles icons on some of walls and large Arabic signs that represent the names of God. There were also about a million tourists.