The castle in Stapelen was first time mentioned in 1293 when it was donated to Willem I van Boxtel. Hendrik Mahie restored the castle in the 19th century to the current Neo-Gothic appearance. The oldest parts of the castle, like the octagonal tower, date from the Middle Ages and the walls from the 16th century. The chapel has a altar from the 17th century. Today Stapelen castle is a monastery.
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.