My Dad was the one who turned me onto tunneling. He took me into the basement of his high school, Lane Tech in Chicago, for his class reunion when I was about five. One might think that a small child would be scared in the deep dark depths of a strange building, but I was fascinated. The fist thing I do when I have access to a new building is see which doors are unlocked so I can explore the infrastructure. I couldn't get to every tunnel, but I explored well over half the campus from under ground. I never had the courage to cut a lock. The forgotten storage spaces were cool. It's unbelievable what kind of old science equipment you can find down there. I think the neatest part was where the old part of campus meet the new part of campus. The old steam tunnels where more like a never ending crawl space. It was a little claustrophobic and creepy having to do the army crawl...I never went past the first building of that section. I also always had a little fear of running into a crazy homeless person down there. If I was homeless, that's where I would go for shelter. At my campus, you didn't have to enter through the access grates. Every building had at least one access point to the basement that was an unlocked door. About 10 or 15 years ago, I found a great website that had numerous lock picking techniques because one the the first rules of tunneling etiquette is to not leave any evidence that you were there. I tried to pick a few locks, but I could not pick anything more difficult than a simple file cabinet. The website wasn't up very long either...LOL...I guess someone didn't think lock picking was a good thing for the general public to know.