The humble trig point celebrates its 80th birthday today.
"On 18 April 1936 a group of surveyors gathered around a white concrete pillar in a field in Cold Ashby and began the retriangulation of Great Britain" The Ordnance survey blogged earlier.
"That trig pillar is still standing 80 years on, along with thousands more around the country."
Back in the 30s they were essential to provide a firm base for survey teams' theodolites. Cartography has since moved on however, and their chief role today is letting hillwalkers know they've reached the top on misty days.
Roughly 6500 of these quirky little pillars were built, and believe it or not someone's actually just finished visiting them all. We'll be interviewing him shortly. Meanwhile here are a couple more trig point photos: