About 90 miles northeast of Paris, the Chemin des Dames is a ridge in a region of Picardy, with centuries old chalk mines underneath. During World War I, the Germans, the French, and the Americans all occupied these mines at one time or another. Writer Richard Rubin set off in search of the mines, and found a time capsule, covered in graffiti.
Learn more at pbs.org/americanexperience.