Thessaloniki is an ancient Greek city with a history dating back thousands of years. Some notable figures from Thessaloniki's past include Alexander the Great and Roman emperor Galerius, who developed the city in the early 4th century AD, building structures like his palace complex, arch, and the Rotunda. The document describes some of Thessaloniki's historical landmarks from its ancient, Byzantine, and Ottoman periods, including the White Tower, old neighborhoods, churches, baths, and walls. It highlights how some parts of the city have changed over time or remained preserved, showing Thessaloniki's long history.