Just a short train ride away from Lisbon, the city of Sintra is a must see. It's best known as the site for the National Palace of Pena, the colorful Romanticist Castle and one of the Portugal’s Seven Wonders. Other places to see in Sintra include Castelo dos Mouros (Castle of the Moors) and Quinta da Regaleira (a lavish garden estate and UNESCO World Heritage Site).