Will Millard included caves in his previous series, but now it's abandoned buildings, with coal mining half way through:
https://www.bbc.co.uk/iplayer/episode/m0014zsh/hidden-wales-last-chance-to-save
Plus a poetic approach to tin mining:
https://www.bbc.co.uk/iplayer/episode/m0014zrj/cornwalls-red-river
https://www.bbc.co.uk/iplayer/episode/m0014zsh/hidden-wales-last-chance-to-save
Plus a poetic approach to tin mining:
https://www.bbc.co.uk/iplayer/episode/m0014zrj/cornwalls-red-river