In 963 AD Emperor Otto I granted to Adalberto Bishop of Luni ownership of the castrum Sarzanae, a fortified village where today the fortress of Sarzanello is located.
Cittadella or Fortezza Firmafede was the first fortress in the city built in 1249. It was destroyed by the Firenze army led by Lorenzo de Medici in 1487 and rebuilt after the war by Medici. It was reconquered by Genoa Republic in 1494.
Today the massive square form building is used as a venue for culture events and exhibitions.
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.