Back in the 19th century, gold miners started digging into the side of a mountain in South Dakota. They dug and dug and dug until, 126 years later, the hole was over a mile and a half deep. In 2001, with gold prices in decline, the gold mine shut down. According to physicist Rick Gaitskell, scientists quickly realized that a hole that deep is the perfect place to search for the single most elemental thing in our universe. We speak with writer Kent Meyers about this ongoing experiment, and then producers Damiano Marchetti and Andy Mills journey to the bottom and find the (radioactively speaking) quietest place in the known universe.

Special thanks to Connie Walter, Matt Kapust and folks at the Dakota Spur Hotel.

This segment featured music by Ken Camden thanks to the fine folks at Kranky.