We took the train to Sintra, a town about an hour west of Lisbon. Like Marvao and Ronda, Sintra is centered around a defensible place, the medieval Castelo dos Mouros perched high on a hill with commanding views (or so I've read) of the Atlantic as well as the surrounding countryside. Today Sintra is a popular tourist destination, dotted with charming squares and quirky buildings such as the Castelo, the Pena National Palace and the Sintra National Palace.
After arrival we grabbed lunch then hiked from the town center up to the castle where we explored the ruins, then we hiked to the Pena Palace where we visited what was once the summer home of the royal family. The palace is full of period pieces like furniture, kitchenware, and bath fixtures. Unfortunately the weather didn't cooperate so the higher-elevation sites, like the castle and palace, were shrouded in clouds. From what I've read, the castle and palace should have amazing views, but I didn't see much of anything but clouds.