Istanbul makes UNESCO – the United Nations Educational, Scientific and Cultural Organization – list for most culturally significant places that provide Outstanding Universal Value. The city has been culturally and historically significant for more than 2000 years. One of the most amazing sites within the UNESCO recognized heritage site of Old City is the Hagia Sophia – from the Greek: Ἁγία Σοφία, “Holy Wisdom“; Latin: Sancta Sophia or Sancta Sapientia; Turkish: Ayasofya (Wikiepdia). The name is apt – the structure was a church – originally an Orthodox and then Catholic – from 360 to 1453. From that date until 1931 it was a mosque. It was closed, secularized and opened as a museum in 1935. For more on the site, visit Wikipedia. It’s appeal is a lot like the khamsa, it’s a polygot sacred site.
Like Rome, Istanbul is called the City of Seven Hills. Popular belief is that on each hill top rests a mosque. But no mosque in the city is quite comparable to the 16th century Sultan Ahmet Mosque, popularly known as the Blue Mosque for the blue tiles on its interior. This is not the oldest mosque in the city, but definitely one of the most formidable.