St. Anthony Falls has long been one of Minneapolis' top attractions, particularly since it powered the factories that made the city into a milling hub.
But the endurance of the falls is due to some complex infrastructure designed to halt erosion. A key component of that infrastructure is a hidden wall — buried beneath the river — that has protected the falls for roughly 145 years.
Little is known about the wall's condition, however. River historian John Anfinson believes there needs to be a comprehensive study of the structure's status.
Anfinson is the former superintendent of the national park comprising the Mississippi River in the Twin Cities. He joined the Curious Minnesota podcast to discuss this mysterious wall.