Begun in the 16th century by Hernando de Vega over remains of a 10th century castle, the Grajal de Campos Castle was finished by his son Juan de Vega y Acuna, count of Grajal. Designed to withstand the use of artillery the castle has sloped walls and its overall height is lower than those of earlier castles, making it difficult and hard to target by cannon fire.
The Grajal de Campos Castle has a square plan with four corner towers covering all blind spots and it is located on the western edge of the village over a small hill. In this same village there is a renaissance palace owned by the same counts which is said to be linked by an underground tunnel with the castle.
To this day, the castle belongs to the actual Duke of Alburquerque, its interior is dismantled and can be visited.
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.