The tiny town of Sintra sits at the foot of the mountains, a 45min. train ride west of Lisbon. Quirky romantic castles and ancient fortresses look down on the small city from the surrounding hillsides, with more palatial residences a couple of kilometers away. Sintra and the stretch of mountain range just west of it are classified as a World Heritage Cultural Landscape by UNESCO, and castle-hopping visitors will surely understand why.