The Pena Palace is a Romanticist castle in São Pedro de Penaferrim, in the municipality of Sintra, on the Portuguese Riviera. The castle stands on the top of a hill in the Sintra Mountains above the town of Sintra, and on a clear day it can be easily seen from Lisbon and much of its metropolitan area. It is a national monument and constitutes one of the major expressions of 19th-century Romanticism in the world.