In June 2018, a resident of Butte felt the ground move. When he stepped outside, he saw a 30-foot sinkhole in his backyard.
Turns out, a shaft in the Carrie mine (one of Butte’s hundreds of mines) had fallen in.
The week before, the homeowner’s children had played in a wading pool on that very spot (the kids were inside when the sinkhole appeared).
The Carrie mine opened in 1885, and a decade later, the house was built. During Butte’s heyday, its residents often built as close to head frames as possible to eliminate time spent in the cold walking to and from work in the mines.
For more on the mine collapse, see the Montana Standard’s article.