I feel like under ground boring must have had a bit of a moment back in the 70s as that was when the Kola super deep bore hole project kicked off. https://en.m.

I feel like under ground boring must have had a bit of a moment back in the 70s as that was when the Kola super deep bore hole project kicked off. https://en.m.wikipedia.org/wiki/Kola_Superdeep_Borehole https://en.m.wikipedia.org/wiki/Kola_Superdeep_Borehole