D.U.M.B.S “EXPOSED”

A “Deep Underground Military Base” is a subterranean facility used for military or scientific purposes. Examples are: Cheyenne Mountain Complex Chiashan Air Force Base Iranian underground missile bases Raven Rock Mountain Complex Zeljava Air Base There may be more than 10,000 underground military facilities worldwide.

LINK:
https://www.popularmechanics.com/technology/design/g152/strangest-military-bases-gallery/