Safety should be a primary concern of every urban explorer. It's easy to underestimate the very real dangers of going underground (or overground) in the city and on campus. Don't make that mistake! Here are safety tips for tunnels, drains, and abandoned buildings. If you have any suggestions, please use the "submit info" link at the bottom of the page to let is know. And remember, Urban Explorers Network does not endorse its readers doing anything illegal. Application of this information in a real world setting is an at-your-own-risk proposition.
Some general guidelines. First, always let someone trustworthy know where you're going. Second, avoid exploring by yourself unless an uncommon and irresistible opportunity presents itself unexpectedly. Third, check the equipment list and be sure to have the top four "American Express" (don't leave home without it) items: light, batteries, gloves, and a knife. Fourth, be aware of your surroundings. Know how and when conditions may change to affect you (for example, a routine janitorial shift change which will put people in your area), and notice the physical (like a ladder which may be unbolted from the wall halfway down). Now, onto specifics.