脕惫颈濒补's splendid 12th-century walls stretch for 2.5km atop the remains of earlier Roman and Muslim battlements and rank among the world's best-preserved medieval defensive perimeters. Two sections of the walls can be climbed 鈥 a 300m stretch that can be accessed from just inside the Puerta del Alc谩zar, and a longer (1300m) stretch from Puerta de los Leales that runs the length of the old city's northern perimeter. At dusk they attract swirls of swooping swallows 鈥 and they're magical when floodlit at night.
Raised to a height of 12m between the 11th and 12th centuries, the walls have been much restored and modified, with various Gothic and Renaissance touches, and even some Roman stones reused in the construction.