Did you know mail used to be sent underground in New York City and other U.S. cities?  Imagine an underground world where mail was zipping around in tubes beneath the incredibly crowded and busy New York City streets. That’s what was happening for over half a century 4 to 6 feet below street level. In this episode, host Michelle Young, the founder of Untapped New York, will explain how the system worked and how the technology can still be found today. Special guests: Lynn Heidelbaugh, Curator at the Smithsonian National Postal Museum; Luke Kingma, former Vice President at the science magazine Futurism; Justin Rivers, historian, playwright and Chief Experience Officer at Untapped New York. Music by Kittens Ablaze ("Hotel Room", "Liarbird"), Absent Tiger ("Take it or Leave It"), and additional sounds by Ben Bynum and Mike Koenig. New York City skyline in icon by Bernadette Moke, the Downtown Doodler.