I generally know the people I link to. However, I do have some links on Urban Exploration (UrbEx) and I don't know all of the content on those websites and I am not advising you to break the law by breaking and entering or simple trespass. In fact, I advise you not to do these things. Since there are hundreds of people out there doing it right now, why not learn from their experiences?
Part of the beauty of the virtual world is you can see many of the hazards you might encounter in urban survival situations by visiting the UrbEx websites. You can also read accounts of these rather unique hobbyists escaping and evading police and security personnel and just a plethora of other topics that could prove very valuable one day.