In the summer of 2014, a sinkhole in downtown Cedar Rapids cracked open a forgotten chapter of American history. Beneath the city, engineers discovered vast brick-lined chambers—19th-century beer caves once used to store thousands of barrels before refrigeration changed brewing forever.

These underground vaults tell the story of immigrant brewers, the rise of Iowa’s beer industry, and how Prohibition sealed away a hidden world. In this episode, we uncover how these caves were built, why they vanished, and what remains today beneath the streets of Cedar Rapids.