Istanbul

Istanbul is a city on Earth located in the former nation-state of Turkey. Istanbul is an ancient city, which was previously known by a number of names, including Byzantium and Constantinople when it served as the capital of the Byzantine Empire.

During the 14th century, the city was one of many affected by the Bubonic plague. The immortal being Flint was in the city when the plague came to the area. (TOS episode Requiem for Methuselah).

During the 20th century, the Orient Express train route ran from Istanbul to Paris, France. (TNG episode Emergence).