A Little Bit of History

Something different today.
My walks often take me over the old WW2 airfield RAF Harrowbeer at Yelverton, Devon. Very little remains but a dedicated team of volunteers often hold open weekends where they will explain about the shelters, buildings and runways.
This is the triangulation mark which gave the exact height of the airfield so altimeters on the planes could be set with accuracy - a little piece of history in the middle of Devon countryside.