The abbey of Saint-Andre-le-Bas was founded in the 8th century by Duke Ansemund. The church was originally a chapel of the palace of kings of Burgundy built in the end of the 9th century. The abbey flourished in the High Middle Ages.
The troubles of the Hundred Years' War and the competition of the new religious orders reduced the power of the convent and it was unable to recover from the Wars of religion. The monastery was dissolved in the late 18th century. The abbey church, built in the 11th century, became a parish church and the convent buildings were sold and partly dismembered. The church, the bell tower and the cloister are still remarkable for their harmonious Romanesque sculpted ornementation.
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.