Portalegre Castle

Portalegre, Portugal, Portugal

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Portalegre Castle in Portalegre, Portugal, was constructed around 1290 during the reign of King D. Dinis to defend the strategic Upper Alentejo border near Spain, incorporating Gothic military architecture with an irregular octagonal layout atop the historic center's highest point.

Its standout square keep tower, vaulted floors, and three surviving towers from an original twelve—including the tall northern tower—overlook the city and countryside, while a double oval wall system with seven gates once encircled the town.

Besieged in 1299 during Dinis's civil war with his brother, later reinforced in the 17th century with star forts, it declined amid 19th-century urban growth before National Monument classification in 1922.