In college there were always rumors about students tunneling, an activity that supposedly was grounds for immediate expulsion. The rumors were more about MIT fraternities using Wellesley’s steam tunnels for secret rituals, rather than our own students running around underground, but I often wondered what was behind those padlocked basement doors. When there was snow on the ground, the track of the steam tunnels was obvious as the heat would melt the snow above. But I never braved the chance for expulsion. There are numerous websites devoted to college tunnels, such as UC Berkeley. Wired wrote about it in 1993. Away from campus, explorers conquer inaccessible areas of cities, such as hidden sections of Grand Central Station in NYC. You can’t get expelled but you can get fined and jailed for trespassing. These urban explorers often seek out abandoned buildings in their modern archeological excursions. Last year, a documentary was released chronicling the homeless who took shelter in abandoned Amtrak tunnels underneath Manhattan.