.. opened in Cornish backyard, leading 300ft down into a medieval mineshaft. https://www.dailymail.co.uk/news/article-3491246/Amazing-pictures-300ft-Cornish-mineshaft-captured-drone.html
I'd tie off a rope and head down there to investigate :D It's only the opening that's collapsed, the ground around it looks stable.
- The Bar 1.3 -