Puig de Missa is a 16th-century fortress-church perched on a hill overlooking Santa Eulària des Riu. Built for protection against Turkish and North African pirate attacks, it's one of the best-preserved examples of Ibiza's defensive church architecture. The whitewashed church with thick walls served as a refuge for villagers during raids. Its hilltop location offers panoramic views over the town, the river (Ibiza's only one), and the Mediterranean. A small ethnographic museum is housed in adjacent buildings.