Built by the Arabs in the 18th century, this castle played a highly important role from a military perspective and was taken from the Moors once and for all in 1147 by the first king of Portugal, Alfonso Henriques. This fortress lies 3 km south of Sintra and can be accessed via a charming hiking trail starting to the left of the Parque da Libertade, though all that remains are the ramparts, as well as its parapet walk which moulds to the rugged terrain and offers a unique vantage point for taking in the amazing landscape, stretching from Lisbon bridge to Cabo da Roca, the westernmost point of continental Europe.