Colsterdale towers

The Colsterdale towers are a set of sighting towers in and around Colsterdale, North Yorkshire, England. These sighting towers were used to conduct surveys during the construction of Leighton reservoir and Roundhill reservoir, other proposed reservoirs and accompanying pipelines. Visible from Roundhill Reservoir and Leighton Reservoir above Arnagill Crags is a stone sighting tower built over an aqueduct near a water-pumping station. The similar Carle Tower is 1.9 miles (3 km) southeast just above Wandley Gill, Carlesmoor Sighting Tower is a further 1.2 miles (2 km) east and another sighting tower to the north is long since gone, having been constructed of wood. The Greygarth Monument is also in the area, commemorating Queen Victoria's Diamond Jubilee in 1897.

Building data from Wikidata (CC0); heights normalised. Summary from Wikipedia (CC BY-SA).