Büren Castle was built in 1621-24 as the residence of the Bernese Landvogt over the area. It was built on the site of four farm houses. Between 1624 and the 1798 French invasion a total of 77 Landvogts lived in the castle. Some of the bullet scars from the troops that invaded in 1798 are still visible on the castle walls. Today the castle is home to the municipal administration and government offices. In 2003 the 17th century murals and other art were restored to their original appearance.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.