Emerging from the foothills of Sintra Mountain, the once-royal sanctuary is now open to the people. Take the train from Lisbon for a day trip to explore the 9th-century ruins of Castelo dos Mouros, stroll the hidden trails of Pena Park with 2,000 varieties of plant-life, and imagine yourself in the shoes of a royal as your footsteps echo through the elaborate interior halls of Pena Palace. Then go to Tivoli Palácio de Seteais for a long, leisurely lunch, followed by a visit to Quinta de Regalieria, where you can wander for hours around the Game of Thrones-like castle, pausing for pictures at the subterranean tower.