Have you ever seen one of these symbols on your walks? They are often on metal plates with a number, but sometimes they are carved into rocks or walls.
I saw this one on a walk on Ruddland Rigg in Farndale. I was on a recce for one of our North Yorkshire guided walks.
It was tucked away next to the entrance to a tiny cave. It looked like a magical sign a goblin, hobbit or elf would make.
In fact, these symbols are bench marks and were used by surveyors from the Ordnance Survey to study the rise and fall of the land and create the detailed maps we have now.
This article has more information.