The Alcázar of Toledo was originally a Roman palace from the 3rd century, but it was restored under Charles I (Holy Roman Emperor Charles V) and his son Philip II of Spain in the 1540s. In 1521, Hernán Cortés was received by Charles I at the Alcázar, following Cortes' conquest of the Aztecs.
The façades are Renaissance in style, and it has towers and crenellated defences according to a preliminary design by Alonso de Covarrubias, subsequently completed by Juan de Herrera. After the last reconstruction it became the site of the Army offices and museum.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.