Thessaloniki, Greece.

Overlooking the Aegean Sea in northern Greece, Thessaloniki (Salonica) is the country's second biggest city after Athens. Founded in 316 BC due to its position close to both Bulgaria and Turkey, it has always been a crossroads of various cultures and religions. Its main sightseeing attractions are its UNESCO-listed Byzantine churches, but there are also several Roman monuments (including the Triumphal Arch of Galerius and the 4th-century Rotunda), the 15th-century White Tower on the seafront, and an excellent Byzantine Museum.