In modern times, a few villages have been abandoned due to reservoirs being built and the location being flooded. These include Capel Celyn in Gwynedd, Wales, Mardale Green in the English Lake District and two villages – Ashopton and Derwent – drowned by the Ladybower Reservoir in Derbyshire. In other cases, such as Tide Mills, East Sussex, Imber and Tyneham, the village lands have been converted to military training areas. Villages in Northumberland have been demolished to make way for open cast mines. Hampton-on-Sea was abandoned due to coastal erosion thought to have been exacerbated by the building of a pier.