At the top of Thessaloniki is the old city, Ano Poli and the ancient Roman walls to keep out the Slavs and other Barbarians from the North. It has incredible views of the city below and the port. In 324 BC General Cassander married Thessaloniki, the half-sister of Alexander the Great after the latter's early demise and established a city in her honor. Thessaloniki in the province of Macedonia remained important in Roman and Byzantine times. The great fire of 1917 destroyed almost half of the city and was rebuilt by French architect, Ernest Hebrard. Today Thessaloniki, the second city after Athens is a thriving metropolis.