impromptu shrines depicting personal messages, remembrances left behind by long gone workers. a frozen, constantly moving and shifting network of passageways. >> scott: the walls come in, the ceiling comes down, the floor comes up. >> anthony: requiring constant maintenance. what's supporting this roof? >> scott: compaction of the snow. >> anthony: scott smith runs the crews keeping these tunnels clear and pipes flowing. >> scott: we're in the process of taking the chainsaw depth off the walls and ceiling to make them into a more usable entry. a lot of work. >> anthony: pretty amazing feat of engineering here. the lowest recorded temperature at the south pole is 177 degrees below zero. >> scott: we're roughly at minus 59 right now. >> anthony: minus 59. >> scott: it's fahrenheit. >> anthony: wow, it only feels like minus 20. i can tell you it scorches the lungs and creeps through your heavy outerwear. >> scott: 200 feet below the ground, we've melted a giant enormous lake down there, about 2 million gallons. this takes about 20 inches of snow to make an inch of water.