A sprawling military facility dotted with bunkers for miles now stands abandoned in the American heartland of Edgemont, South Dakota. Experts investigate and uncover the Black Hills Ordinance Depot, a once highly-secure WWII ordnance site designed to store deadly munitions.

The SS United States, a historic sea vessel once considered the pinnacle of American engineering, now rusts in the Delaware River at Philadelphia, Pennsylvania. Experts investigate the fastest passenger liner ever constructed and a masterpiece of marine architecture that doubled as a U.S. warship.