I visited this WHS in August 2014. Knowing that this WHS was actually made up of 4 palaces, a castle and an estate, I decided to dedicate 2 full days to Sintra and sleep over. It turned out to be a great decision. Sintra is choc-a-bloc with cars, coaches, vans and bus loads of tourists mainly from 11am till 4pm as most visit Sintra as a day trip from Lisbon. If it's the only way to see Sintra by all means go for it but still I'd suggest to stick to no more than 3 sites. Having more time to spare, I arrived by car from Lisbon around 9am and there were ample parking spaces to choose from. The parking meter lets you pay a maximum of 2 euros for 4 hours but by registering your number plate online (there are instructions on the parking meter) you can simply pay online or send an sms to extend your parking time. I bought the combined ticket to visit Pena Palace + Moorish Castle + Monserrate and then bought a separate ticket to visit Quinta in the evening. The Seteais Palace is a luxury hotel which I proudly called my home for a night. The Ramalhão Palace is decorated in the Louis XVI neoclassical style and I only saw it from outside. The Pena Palace is the star attraction of Sintra and hence is the palace that attracts most crowds. Visiting early in the morning meant that I managed to beat the crowds so by the time I finished viewing it's colourful exterior and visiting its interior, endless groups of people flooded the palace! Therefore I'd say that timing is of the essence here. The Castle of the Moors is close to the Pena Palace so naturally attracts a lot of people too. At least however it offers more open spaces than the Pena Palace so it doesn't feel so crowded. It's worthwhile climbing the stairs to enjoy the view over Sintra too. My favourite palace is actually situated 4km away from Sintra but I really loved its exterior and interior design with Moghul-inspired details and the lavish gardens. I was very lucky to be the very first visitor early in the morning which meant that for a while I had the palace to myself and I really enjoyed some peaceful and quiet moments. The highlight of my visit though was the mysterious and esoteric Quinta da Regaleira. The Manueline style is immediately visible once you approach the estate and also on the small but enchanting chapel. The gardens are a labyrinth of tunnels, grottoes, statues and fountains full of esoteric symbols. I've never seen anything like the Quinta and I must say it's truly unique. It opens until 8pm in the summer months and occasionally there are private night tours or theatrical events organised on the estate grounds which I wholeheartedly recommend. All in all I enjoyed my visit to Sintra but I'm sure my experience would not have been the same had I visited only as a day trip from Lisbon.