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

The most visited attraction in the area around Cascais is the forbiddingly named Mouth of Hell, one of several natural grottoes in the rugged coastline. Located just 2 km (1.2 miles) west of town, it is best appreciated at high tide or in stormy weather, when the waves crash high onto the surrounding cliffs. You can walk along the fenced paths to the viewing platforms above the grotto and peer into the abyss. A path leads down to secluded spots on the rocks below, where fishermen cast their lines. The bleakly beautiful spot is where English occultist and magician Aleister Crowley faked his own suicide in 1930, shocking onlookers when he appeared at a Berlin art gallery three weeks later. A white plaque at the site marks the intriguing occasion, together with the text of the "suicide note" he left behind.

This salt-encrusted headland—crowned by a whitewashed convent surrounded by 18th-century pilgrim rest houses—is the southwestern point of the Setúbal Peninsula, marked by a red-and-white lighthouse. It's a ruggedly beautiful spot, where the cliffs rise hundreds of feet out of the stormy Atlantic. To the north, unsullied beaches extend as far as Caparica, with only local roads and footpaths connecting them. It's a good spot for hiking, with marked trails leading down to some clearly visible dinosaur footprints.

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.

A favorite destination for runners, hikers, cyclists, and triathletes, Sintra-Cascais Natural Park is renowned for its well-marked trails across the forest-covered slopes of the Serra da Sintra. It's also known for its wild beaches, towering sand dunes, and its abundant flora and fauna The bleakly beautiful Cabo da Roca and its lighthouse mark the continent's westernmost point and are the main reason that non-athletes make the journey to Sintra-Cascais Natural Park. The cliffs tumble to a frothing sea below, and on the cape a simple cross bears an inscription by Portuguese national poet Luís de Camões.