A tourist visiting Istanbul can hardly avoid Sultanahmet Square. It is located on the site of the ancient Hippodrome, which was built at the time of the Byzantine Empire by the Emperor Constantine, based on the model of the Roman Circus Maximus. An about 3,500-year-old obelisk from Egypt is still standing there. The German Fountain, covered by an octagonal roofed gazebo building in Neo-Renaissance style, was also built on the square in 1901 to commemorate the visit of German Emperor Wilhelm II to Istanbul.

But the main reasons to visit Sultanahmet Square are, of course, the adjacent imposing buildings of the Hagia Sophia museum and the Blue Mosque.

The Hagia Sophia, once the coronation church of the Byzantine Emperors, was converted into a mosque after the conquest of Constantinople by the Ottomans in 1453 and has since been turned into a museum, drawing countless tourists every year.

The Blue Mosque was built in the early 17th century by Sultan Ahmet I. Istanbul's main mosque was named after its founder, Sultanahmet Camii, but tourists usually refer to it as the Blue Mosque. Magnificent bright blue ceramic tiles cover its interior walls and pillars.

Many prominent guests have visited these historical buildings, among which Pope Francis during his trip to Turkey in December 2014.

Just a few steps away from the Hagia Sophia is the sprawling complex of Topkapi Palace, the former seat of the Ottoman sultans.

History and culture are not the only reasons travelers head to the Sultanahmet district; the neighboring Grand Bazaar, one of Istanbul's man tourist attractions, also draws bargain hunters.

Attracting annually over 30 million tourists, Turkey ranks as the sixth most popular tourist destination in the world, according to the World Tourism rankings compiled by UNWTO. Travelers from Germany make up the largest group, with 5 million visiting the country every year.