3 ms·
The cave thing is neat - sounds like an easy form of https://en.wikipedia.org/wiki/Geothermal_heating https://en.wikipedia.org/wiki/Geothermal_heating
by rudedogg 9y ago
The cave thing is neat - sounds like an easy form of https://en.wikipedia.org/wiki/Geothermal_heating https://en.wikipedia.org/wiki/Geothermal_heating