Ioannina is the capital of Epirus and one of the most interesting cities in northern Greece — a lakeside city with a well-preserved Ottoman old town, a castle on a promontory jutting into Lake Pamvotis, and a long history as the capital of Ali Pasha's quasi-independent Ottoman domain in the late 18th and early 19th centuries. The old city within the castle walls contains mosques, a Byzantine museum, and the tower where Ali Pasha made his last stand before being killed.
A short boat ride from the castle jetty takes you to the small island in the lake, whose village of monks and old monasteries is one of the most atmospheric places in Greece. Take the boat in the evening, eat grilled eel (the local speciality) on the island's terrace restaurant, and come back after dark when the castle is lit up across the water.