Related, the story of William Lyttle[1], the “Mole Man of Hackney”, is rather fascinating. Dug for years underneath his house and surrounding streets in London.
He was then evicted by the local council, the house sold, renovated by an architect and a well known artist moved in[2].
Another favorite pastime was digging a tunnel under his home; he attributed the secret of his success to "visits by elves" while he worked in the tunnel: "While I'm digging in the tunnel, the elves will often come to me with solutions to my problem."
Many interesting stories of hobby tunnel diggers. I remember a news story a few years ago, a "tech bro" type person had a tunnel project where a guy he hired died (or hospitalized?) due to unsafe working conditions. Ah yes, here's an article about it.
Although not really a hobby tunneler, one of my favorite people on this list is William John Cavendish-Scott-Bentinck, the reclusive 5th Duke of Portland who built an extensive series of tunnels under his estate. His life is fascinating. Recommended reading:
Growing up in Southern California we spent a lot of summers at the beach, and I can attest that spending all day digging a big hole was one of the funnest things to do.
I do really wonder why boys find it so much fun to dig.
Watched this doc on Baldassare Forestiere recently.
Amazing. He dug out acres and acres over his life in Fresno. Was raised as a fruit tree grower in Italy, and has fruit trees growing from down in the caves he made through to the special sky lights
Can remember when the Elton McDonald tunnel in Toronto was discovered but still a mystery. All the “experts” making claims of nefarious this n that. Turns out was just some dude who wanted to dig a tunnel.
He was then evicted by the local council, the house sold, renovated by an architect and a well known artist moved in[2].
[1] https://en.wikipedia.org/wiki/William_Lyttle
[2] https://www.youtube.com/watch?v=Ks5QdYhvHWg