A lot of universities have underground tunnels built to allow students to walk between classes in subzero temperatures. Northwestern isn't one of them. Our tunnels are strictly off-limits to students, but that doesn't stop literally everyone with a taste for adventure and an iPhone from finding their way down at one point or another. Walking through these can take you from the observatory on North Campus to Fisk Hall on South. It's also insanely hot... and incredibly cramped.
The easiest access point is an air vent outside of the observatory. Make your way to the green, tent-shaped cover hidden behind the row of bushes and pull it off to reveal a ladder down into the tunnels. Be very careful not to touch any uncovered pipes with your hands or you will be burnt! If you are sneaky enough, you can climb down the pipes without hurting yourself and get onto the ground into the first tunnel, pictured above. From there, keep walking until you reach the end or leave through one of the many other access points. Remember to close the one you went through on your way in!