South Dakota’s Underground
[google_map_easy id=”79″]
Location: ? Jim River Valley South Dakota
Functions: Unknown
Levels: Unknown
Tunnels to: Unknown
Notes: “A Vast Underground Lake” discovered below the Jim River Valley which spans the borders of both states.
Source:
Location: Black Hills South Dakota
Functions: Unknown
Levels: Unknown
Tunnels to: Unknown
Notes: Plans for a large underground scientific laboratory within a large gold mine in the Black Hills.
Source:
Location: South Dakota
Functions: Unknown
Levels: Unknown
Tunnels to: Unknown
Notes:
Source: