Cascais is small enough to cover on foot in a day, but rewards a slower pace. The historic centre, the seafront, and the walk to Boca do Inferno are the core of any visit. The Museu dos Condes de Castro Guimarães — housed in a romantic waterfront palace — gives a good sense of the town's aristocratic past, and the Cidadela fortress anchors the harbour end of the old town.