I live near this cave and me and my buddies have thoroughly explored it and I can tell you there is no underground city! But I cant tell you if you
are into Spelunking that its one hell of a cave to visit.
I have been in the cave to the meat grinder. I have video all the way and pics as well. All on youtube, batteryphil user name. There is a video of a
Mexican family going in as well they went far as me at least. look at these links www.youtube.com... www.youtube.com... www.youtube.com...
Sorry, but I have to put my hand up and say 'What???' to your second source. That cavern was not 4 miles deep. The deepest mine in the world is the
TauTona gold mine in South Africa and that's 2.4 miles deep - oh and the temperature there is 131F.