The Catacombs of Paris hold many skeletons that are hidden 65 feet underground. NBC News’ Keir Simmons visits the Catacombs and talks to a historian about their history and significance.

The Catacombs of Paris hold many skeletons that are hidden 65 feet underground. NBC News’ Keir Simmons visits the Catacombs and talks to a historian about their history and significance.