Take a break from Lisbon and catch the train to Sintra at Rossio Station. Only 40 minutes away from the city centre, you’ll find this amazing village with several palaces and castles. Monserrate is, for sure, one of my favourites. It looks like you’re in a dream!
Oh, and on the way here, make a stop at Piriquita and buy a Travesseiro de Sintra, the typical pastry of this area. Delicious!