Patras is Greece's third-largest city and its main western port, and it carries both roles with a confidence that the smaller tourist towns of the Peloponnese lack. The city climbs from the harbour up to a medieval castle on the hill, with a Roman odeon on the slope between them that still hosts performances. Below, the grid of streets around Georgiou Square has good cafes, a lively theatre scene, and a university population that keeps the energy high year-round.
The city's greatest annual event is its carnival, which runs for several weeks before Lent and is the largest in Greece and one of the biggest in Europe. If you can time a visit to coincide with the carnival's final weekend, it's worth the planning. Outside carnival season, Patras rewards a day or two of exploration: the cathedral of Saint Andrew is impressive in its scale, the Roman remains are well-preserved, and the views from the castle over the Gulf of Patras toward the Ionian islands are excellent.