The Moorish Castle is an 8th-century fortress built by the Moors from North Africa to defend the region. Its massive walls stretch along the peaks of the Serra de Sintra mountains, offering breathtaking panoramic views of the Atlantic Ocean and the entire region. Although the central keep is in ruins, most outer walls remain intact, with some rebuilt in the 19th century by order of King Ferdinand II. Climbing the ramparts is an adventure that rewards visitors with the best views in Sintra, including Pena Palace perched above. Part of the UNESCO World Heritage Site, the castle provides a fascinating glimpse into medieval military architecture.