At the end of the train line, CASCAIS (cash-kaysh) is a major resort, with three fairly good beaches along its esplanade, a flash marina and a fort (closed to the public) that guards the harbour. It is positively bursting at the seams in summer, especially at weekends, but despite the commercialism it's not too large or difficult to get around, and has a much younger, less exclusive, feel than Estoril. It even retains some vestiges of its previous existence as a fishing village.
You'll find the main concentration of bars and nightlife – and consequently most of what makes Cascais tick as a town – around Largo Luís de Camões. The local fish market near here is worth a look (Mon– Fri from around 4pm), while for a wander away from the crowds, stroll up beyond Largo 5° de Outubro into the old, and surprisingly pretty, west side of town, at its most delightful in the streets north of the graceful Igreja da Assunção.
Cascais' other attractions are all to the west of the centre. Beyond the church lies the pleasant Parque Municipal da Gandarinha, in whose southern reaches stands the mansion of the counts of Guimarães, preserved complete with its nineteenth-century fittings as the Museu Biblioteca Conde Castro Guimarães (Tues– Sun 10am–5pm; 1.65); most days, there's someone around to give you a guided tour of the furniture, paintings and antiques that the count bequeathed to the nation. On the north side of the park, signs point you to the modern Museu do Mar (Tues– Sun 10am–5pm; 1.65), an engaging little collection of model boats, sea-related artefacts, old costumes and pictures.
Taking the coastal road, it's about twenty minutes' walk west to the Boca do Inferno – the "Mouth of Hell" – where waves crash against caves in the cliff face. The viewpoints above are always packed with tourists (as is the very tacky market on the roadside) but, frankly, the whole affair is rather unimpressive except in stormy weather. It's a pretty walk, however, past the marina, backed by rows of modern cafés, shops and restaurants.