My buddy and I used to travel the water drainage tunnels and cement ditches in beaumont, TX. If you can imagine a couple of high schoolers riding their bikes through water in a cement drainage ditch and disappearing into a tunnel, that was us. We also climbed to the top of an abandoned rice elevator. It looked alot like this:
http://www.texasescapes.com/TexasGul...levator904.jpg
I hit a tunnel one time to catch some local catfish for my aquarium, then discovered that the fish were gone. After about a quarter mile, I found the alligator that ran the fish off. He wasn't too pleased and neither was I. Haha.