They're relatively warm places so are conjectured to make a nice(ish) place for the quick rather than the dead. https://en.m.wikipedia.org/wiki/Lunar_lava_tube

They're relatively warm places so are conjectured to make a nice(ish) place for the quick rather than the dead. https://en.m.wikipedia.org/wiki/Lunar_lava_tube https://en.m.wikipedia.org/wiki/Lunar_lava_tube