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

A five-minute walk along the main road past the tourist office takes you to one of Sintra's most intriguing privately owned mansions. Quinta da Regaleira was built in the early 20th century for a Brazilian mining magnate with a keen interest in Freemasonry and the Knights Templar (who made their 11th-century headquarters on this site). The estate includes gardens where almost everything—statues, water features, grottoes, lookout towers—is linked to one or the other of his pet subjects. Spookiest of all is the 100-foot-deep Poço do Iniciático (Initiation Well)—an inverted underground "tower." Audio guides in English are available at reception.

Visitors to this grand mansion dating back more than a century can get a peek into how local aristocracy once lived while admiring an impressive display of 18th- and 19th-century paintings, ceramics, and furnishings. The canary-yellow building makes a dramatic backdrop to the small beach next door, which is open to the public and attracts groups of swimmers and sunbathers on hot days.