In the city itself, we visited Sintra Palace, built from 1415 onwards and continuously inhabited from the early 15th to late 19th centuries. Significant Islamic artistic influence, most notably tilework, is evident in Sintra Palace and many other buildings in Lisbon and Sintra.
The castles built on the hillsides were the real stars of the show, though. Laura and I rented electric bikes - they require peddling but a motor kicks in to make climbing steep hills easier - and headed to higher ground.
The view from the hill-tops in Sintra was incredible! Sintra unexpectedly vaulted into our list of favorite places we visited in Europe; if you're ever in the area, don't overlook this gem. You can see more of our pictures from Sintra on Flickr!