1973

Prior to 1973, one could see military convoys along major freeways of the USA. Often times there were camo~tarp covered trucks with what looked like projectiles underneath. It was a common site for any motorist of that time. Military trucks and jeeps were a common site.

Even though we were in a recession of sorts in 73, there was a major shortage of concrete. Builders were having to import concrete from Mexico that was less then adequate for their building needs. Driveways built of Mexican concrete in Anaheim Hills California during that time have since cracked and fallen apart.

But the question is where was this demand for so much concrete coming from? Some believe the building of underground freeways for government used the concrete. Notice you no longer see military convoys on our freeways. Did they go underground? No one knows, just stay clear of the air ducts protruding from the most unlikly places in the desert...LOL

Here are 7 underground wonders of the world.
http://weburbanist.com/2007/09/30/7-underground-wonders-of-the-world-labyrinths-crypts-and-catacombs/

http://weburbanist.com/2008/04/30/7-more-undergrou ...