Botallack Mine Cornwall

Botallack tin mine is a tin mine located approximately 1 mile from St Just in Cornwall. The mine is part of the Cornish Mining UNESCO World Heritage Site and one of the Poldark filming locations. Accordingly to wikipedia, it "was a submarine mine, with tunnels extending under the sea, in places for half a mile. Over its recorded lifetime, the mine produced around 14,500 tonnes of tin, 20,000 tonnes of copper and 1,500 tonnes of arsenic.

The mine is part of the National Trust and is an amazing place. It's free to access and enjoy the buildings, view, and coastal footpaths. I was in awe of the amazing view. We stopped off there at the end of a sunny day, and I did not have time to explore everything, but I'll be sure to go back the next time I am in Cornwall.

https://www.nationaltrust.org.uk/botallack#Overview

https://whc.unesco.org/en/list/1215/https://www.nationaltrust.org.uk/botallack#Opening%20times