I was told by my brother-in-law that his uncle, who worked for Marathon Pipeline in Dallas, was shown an underground installation that was built during the construction of the highway system surrounding Dallas early on. He was shown ufos, which were described to him as "ours". This is a link to the potential construction data:
http://www.texasfreeway.com/dallas/h...c_photos.shtml
I have not shared this with anyone other than passing comment.