The Church of San Pedro Apóstol is considered a National Historic-Artistic Monument in Vitoria from the 13th-14th centuries. The temple was attached to the western wall of the medieval town, which is why the walls on the west are very thick. In the central nave the walls form a tower which is visible from the outside of the temple.
Gothic façade dates from the 14th century, accessible from Calle Herrería. The entrance is the opposite way round in this church because the wall used to run along the bottom of the central nave.
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.