The main street ("Rua Direita") leads from the town gate (decorated with 18th century tile panels) to the main square (Praça de Santa Maria). It has a beautiful fountain, a 15th century pillory, the Town Museum (with exhibits ranging from archeological finds to 15-17th centuries sculpture and paintings), and Santa Maria Church. That's where 10-year-old King Afonso V married his 8-year-old cousin Isabel in 1444, with an interior entirely faced with tiles and containing the tomb of Joăo de Noronha, the castle governor who died in 1575. Closeby is Misericordia Church (with a fine Baroque doorway), while outside the walls is the Amoreira Aqueduct, built at the behest of Catherine of Austria in 1575.
The best way to experience the romantic atmosphere of the village is to stay overnight when most visitors are gone. Try booking the castle hotel, part of the Pousadas network, well in advance -- you'll really be filled with medieval romance when you step outside and find the walls floodlit and the narrow alleys brightened by the moonlight.