Several prehistoric settlements and remains of a Roman road station have been discovered in Welschdörfli, the old town district in Chur. You can visit the excavations and discoveries on the Ackermann grounds on Seilerbahnweg.
The protective structures covering the archaeological sites from the Roman era were built in 1986 according to designs by local architect Peter Zumthor. They do not only protect the finds, they are also a museum and architectural masterpiece. The weighty building with its delicate rilled outer surface is reminiscent of the original Roman edifices.
You can get the key to the protective structures from the Chur Tourism information centre at the station.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.