Istanbul, Turkey

An unusual fact: Istanbul is the only city in the world located on two continents: Europe and Asia. The Bosphorus Strait separates them, connecting the Black Sea with the Sea of Marmara. Istanbul is home to the Hagia Sophia, one of the greatest architectural structures, built in 537. It has been a cathedral, a mosque, and is now a museum. The city has around 3,113 mosques, including the famous Blue Mosque with its six minarets.