2 Best Sights in Sintra, the Estoril Coast, and the Setúbal Peninsula, Portugal

Occupying the entire southern coast of the Setúbal Peninsula is the Parque Natural da Arrábida, dominated by the Serra da Arrábida—a 5,000-foot-high mountain range whose wild crags fall steeply to the sea. There's profuse plant life at these heights, particularly in spring, when the rocks are carpeted with colorful wildflowers. The park is distinguished by a rich geological heritage and numerous species of butterflies, birds, and mammals (you might spot foxes and mongoose, and even wild boar). The park is a favorite destination for bikers, hikers, horseback riders, and adventure-sports enthusiasts. There are also some lovely hidden beaches for those prepared to put in the footwork.

The battlemented ruins of this 10th-century castle still give a fine impression of the fortress that finally fell to Christian forces led by Dom Afonso Henriques in 1147. Panoramic views from the serrated walls explain why the Moors chose the site. It's visible from various points in Sintra itself, but for a closer look follow the steps that lead up to the ruins from the back of the town center (40 minutes going up, about half that coming down). No cars are allowed, but you can save your legs by catching Scotturb Bus 434 or taking a tuk tuk ride from town. The castle is walkable from the Palácio da Pena, since it's accessed from the same road and its entrance is somewhat below that of the Palace park.