The Walls of Évora are a defensive fortification spanning centuries of history, with layers from Roman, Moorish, and Portuguese medieval construction. The oldest sections date to the 1st century BCE during Roman rule, later rebuilt by Visigoths and Moors. In the 14th century, King Afonso IV ordered their expansion with new towers and gates. Significant portions still stand, including the gate towers of Avis, Baluarte, and São Bartolomeu. A walking circuit around the walls takes about 2 hours and offers fascinating views of the city's historical layers. The walls were declared a National Monument in 1922 and form part of the UNESCO World Heritage site.