From its headwaters in West Virginia right to its estuary in Maryland's Chesapeake Bay, the Potomac River became a front line during the Civil War, ripping the nation in two. On the banks of the river at Harpers Ferry, a key federal armory was raided by abolitionist John Brown in 1859. Passing through Washington D.C. and the national monuments along the Tidal Basin, the journey ends at George Washington's Mount Vernon estate in Virginia to learn about the future president's survey of the upper river during his teenage years.