The emperor Galerius built himself a palace in Thessaloniki. After all, his co-emperor Diocletian was building himself a splendid palace at Split, on the Dalmatian coast. Little remains of Galerius's royal home, but even these low ruins give you an idea of the size of the two-story palace with its large central courtyard -- fit, in short, for an emperor. The best-preserved part of the complex is the Octagon, the building that some archaeologists think may have been Galerius's throne room. The Octagon, opulent and richly decorated with a multicolored marble floor, had two interior recesses. One, a good deal larger than the others, would have been ideal for a throne. That said, it should be noted that a very similar structure built by Diocletian in Spoleto, Italy, was not a throne room but a mausoleum. Allow half an hour here.