Sintra is both a town and a municipality in Portugal, located in the district of Lisbon. The municipality of Sintra is the second largest in Portugal by population, after Lisbon. The town is a UNESCO World Heritage Site on account of its 19th century Romantic architecture, it is a major tourist attraction, with many day-trippers visiting from nearby Lisbon. Attractions include the Palácio da Pena (19th c.) and the Castelo dos Mouros (reconstructed 19th c.) in the Serra de Sintra nature park, and the Palácio Nacional de Sintra (largely 15th/16th c.), in the village itself.