Built by the Moors, Lagos' castle was conquered by Christian forces in the 13th century. It's said that the ill-fated, evangelical Dom Sebastião attended an open-air Mass here and spoke to the assembled nobility from a small Manueline window in the castle before leading them to a crushing defeat at Alcácer-Quibir (Morocco). What little remains today is well preserved; after admiring the window, check out the nearby bastion and gateway.