Dunnose
United Kingdom
Dunnose is a cape on the Isle of Wight in the English Channel. The headland is visible from well out to sea, and is used in navigation. It has twice been used as the base point for a triangulation of Great Britain. The line of accurately surveyed points running north from Dunnose to Clifton in Yorkshire provide the basis for triangulation to determine the positions of all other locations in Britain.
Data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).