Fort Vechten was constructed between 1867 and 1870 as part of the so-called Nieuwe Hollandse Waterlinie (The 'New Dutch Water Line') to defend the cities of the western Netherlands from overland attack.
The history of Vechten dates however back to the Roman times. The Romans, who apparently chose the spot because it controlled a side-arm of the Lower Rhine, built their castellum by the year 4 AD, and possibly named it after that river, Fectio. This fort was quite important from time to time as a supply-base for the invasion of Germany. It attracted the local population as well, which came to settle in the vicus at either end of the fort. The castellum was most likely abandoned by the late 3rd century, when the Roman Empire faced crisis after crisis. However, the main reason that the army never returned may well have been because the access to the fort silted up, which caused it to become land-locked, with all the ensuing logistical problems. The neighboring castellum at Trajectum/Utrecht may have supplanted it as local fort. Today there is a reconstructed Roman watch tower.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.