Ptuj's historic centre is compact enough to cover on foot in a half-day, but rewards a slower pace. The hilltop castle dominates from above and is the obvious starting point, with the old town spreading down the slopes toward the Drava river. The Roman heritage is less visible but surfaces in a fine collection of stone monuments, and the Orpheus Monument in the main square is a striking reminder that Poetovio was once a significant city of the empire.
The Kurentovanje carnival in February is one of the most distinctive folk traditions in Slovenia — if you have any chance of timing a visit around it, do so.