Want to explore a military complex that is open to the public? Check these links out!
http://www.huntmidwest.com/pdfs/subsitemap.pdf
http://www.huntmidwest.com/pdfs/subtropolis_bro.pdf
http://www.huntmidwest.com/subtropolis/movies.html
This system is massive and housed a large portion of the military equipment during the height of the cold war. This is one of many complexes turned over to the public for use. This is an example of putting cold war fears back into productive uses.
Here is a military complex you can enter, safely!