Inside Pluto’s Cave, the Northern California cavern that dips 1,200 feet into the ground

San Francisco Gate ^ | Silas Valentino ,

[SunkenCiv]

Building habitats in lava tubes on the Moon and Mars has been a serious discussion for a while.

Pluto's Cave Holds a 100 Year Old Secret, Mt Ashland Primitive Camp
Vanlife Sheldon's Travels | 14.1K subscribers | 6,150 views | July 19, 2019

[major_gaff]

See! I was paying attention in that Humanities class the PSU College of
Engineering insisted that I take.

[SunkenCiv]

Those buncha liberals, whaddya expect? ;^)