While students walk on the crowded sidewalks, they are largely unaware that they are also walking above a maze of tunnels used to heat buildings across campus. These tunnels remain a secret to most of us—except for a few adventurous souls who have dared to venture in, despite the risk of a trespassing charge. The white labyrinth is lit with dim lights, covered with spider webs on the sides and located about two to eight feet under the ground. Groundwater puddles, mineral deposits and leaves drawn in from occasional openings cover the floor of the 4.3 mile long tunnel system. The oldest pipes are more than 100 years old and still in use.