Observation Tube

The Observation Tube, better known as the "Ob Tube" offers one of the most fascinating views at Antarctica's McMurdo Station. Installed annually into the sea ice, the tube descends 20 feet into the frigid ocean below. Glass windows at the bottom let viewers see the fish, seals, jellyfish, and other wildlife swimming. Looking back up, the underside of the sea ice appears blue-green because of the algae growing on it.

From the surface, the Ob Tube looks a little like one of the pipes that Mario jumps into. The opening measures just three feet across, so only one person is allowed down at a time. (Several people have gotten stuck and needed to get rescued!)

After climbing into the Ob Tube, you'll find metal hand and foot holds for most of the 20-foot journey, followed by a short section of rope ladder. Once you reach the bottom, windows allow you to see out in every direction.

The Ob Tube is also an excellent place to hear Weddell Seals. Their otherworldly trills and chirps, which to some sound like robots or even aliens, travel far underwater.