Sintra sits in a fold of hills just west of Lisbon that catches the Atlantic damp and holds it, so the town spends much of the year under a soft grey ceiling. That fog is not a nuisance; it is the whole aesthetic. The nineteenth-century Romantics who built here wanted their palaces to loom half-hidden, and on a misty morning Pena Palace does exactly that, red and yellow towers swimming out of the cloud above the trees.
The three great sights sit high and apart. Pena Palace crowns the top ridge, a giddy mash-up of turrets and tilework you reach by a steep climbed path or a shuttle bus. The Moorish castle walls run along the next crag over, a serrated line you can walk end to end for the drop-away views. Down in the valley, Quinta da Regaleira hides its famous initiation well — a spiral staircase bored straight down into the hillside.
The one hard truth about Sintra is the traffic. The N247 and N375 that thread up to the palaces are narrow, walled and permanently jammed by tour coaches, and parking near the top barely exists. Do not drive up. Leave the car down in the town or at the station, and take the 434 loop bus that runs Pena, the castle and the centre in a circle. Your rental will thank you for the day off.
Timing beats everything here. Book the first entry slot of the morning, before the coaches arrive from Lisbon and while the mist is still doing its work. By eleven the queues coil back through the gardens and the magic thins with the crowd. Come at opening, walk the Regaleira tunnels while they are empty, and be back down in town for lunch when everyone else is only starting to climb.
Save the afternoon for the quieter corners — the peeling grandeur of Monserrate, a café in the old centre, the road on toward the coast at Cabo da Roca. Sintra rewards the patient and punishes the rushed. Pick the car back up in town when you are done, and drive out the way the day cools, downhill and west toward the sea.