Humm List of DUMBS by state

[F2d5thCav]

Two miles down?  Wouldn't people need pressure suits to come and go without getting the bends?

I've seen underground military facilities, but to the depth of a couple of stories, not MILES.

The Germans liked tunnels and underground facilities.  There were still remnants of those in and around the U.S. bases in Germany that were taken over in 1945.

Cheers