Only 28km away from Lisbon, Sintra is primarily known because of the Pena Palace (Palácio de Pena), built in the 19th century in an eclectic style by the Portuguese king-consort Dom Fernando II. Close by, the Castelo dos Mouros (Moorish Castle) is also an important landmark and a popular tourist destination. The town of Sintra itself boasts the medieval Sintra National Palace and several 19th century estates. Sintra and its surrounding mountains (Serra de Sintra) are classified as a UNESCO World Heritage Site. It is a popular destination for day-trippers, and can be easily explored while staying in Lisbon.