Thessaloniki has many sights. The most famous sight in Thessaloniki is the white tower. The White tower was a part of Thessaloniki's ancient walls that were built many times through the ages. Thessaloniki was the second-most well-fortified city in the Byzantine Empire, after Constantinople (Istanbul). The walls can still be seen above the city today and despite the many earthquakes, they are still standing. The city was home to a Roman imperial palace and mausoleum. The palace ruins can be seen today but the mausoleum together with a Roman arch can be still seen standing today. Very important sights of Thessaloniki are the medieval churches such as Agios Dimitrios, Agios Georgios and Agia Sofia. Agios Dimitrios it the largest and oldest Basilica in Greece. Thessaloniki's Christian monuments are part of the UNESCO World Heritage initiative. The city also has many Ottoman monuments, such as the Bey Hammam and the old district of the city near the walls, with its distinctly Turkish architecture. Many museums are in the city and some of them are: Archaeological Museum of Thessaloniki, Museum of the Macedonian Struggle, Jewish Museum, Ethnological Museum of Macedonia and others. 