Castelo dos Mouros (Moorish Castle)
This castle was built in the 10th century by the Moors to defend the town of Sintra. Apparently, when Cascais was under the rule of Sintra, a huge fire would be lit here annually to remind the people of Cascais that the castle was there to protect them. It was further enlarged after the Christian reconquest in the 12th century. The complex was restored in romantic style by Dom Fernando II.