Lake Vyrnwy (photo courtesy of Vince Jones)
Lake Vyrnwy Nature Reserve and Estate is an area of land in Montgomeryshire, Powys, Wales, surrounding the Victorian reservoir of Lake Vyrnwy. Its stone-built dam, built in the 1880s, was the first of its kind in the world.
The gothic building is a straining tower used to sieve the water. The Reservoir was built in the Victorian era to supply Liverpool’s water.
(Photo from Wikipedia)