Monday, August 11, 9-10 pm ET
An intact artillery shell that may have been part of an attack on the U.S. in WWI; etched glass that may depict the cruiser commanded by Commodore George Dewey; and a house that may have guarded against attacks during the French and Indian Wars.

Black Tom Shell - A woman in Whitehouse Station, New Jersey, has an explosive artifact in her possession: a large, intact artillery shell, along with a note in her mother's handwriting that reads "Black Tom Explosion of 1914." The contributor's mother's record-keeping is off: It was not 1914, but July 30, 1916, when a German spy ring carried out a well-planned set of synchronized explosions on Black Tom Island in New York's harbor, using the United States' own cache of munitions produced to aid Britain and France in World War I. Two million pounds of exploding ammunition rocked the country as far away as Philadelphia and blew the windows out of nearly every high rise in lower Manhattan, injuring hundreds. HISTORY DETECTIVES host Gwendolyn Wright travels to Maryland and New Jersey to determine whether this shell was involved in one of the earliest foreign terrorist attacks on American soil

USS Olympia Glass - The door of a farmhouse in eastern Nebraska has an etched glass window with a depiction of a ship cruising through open waters, smoke pouring from its stacks. The home's owner believes the ship is the USS Olympia , the cruiser commanded by Commodore George Dewey when he defeated Admiral Montojo's Spanish squadron at Manila Bay in 1898, beginning the Spanish-American War. The farm's been in the family for more than half a century, and a 1977 letter from the USS Olympia Association states that etched glass windows may have adorned Admiral Dewey's own stateroom. HISTORY DETECTIVES host Wes Cowan travels to Fremont, Nebraska, and Philadelphia to find our whether the unique window can serve as a portal into a turning point in American foreign policy.

Front Street Blockhouse - When a couple in Schenectady, New York, purchased their dream house in the town's historic district, they believed their home was built for a middle-class family in the late 19th century, like all other homes in their neighborhood. But four mysterious stone walls visible in the attic have led them to believe otherwise. Did this house once guard against enemy attacks during the tense years of the French and Indian Wars - nearly 300 years ago? HISTORY DETECTIVES host Elyse Luray travels to Upstate New York to determine whether this unassuming structure may have helped ensure the survival of the town of Schenectady, a 17th- and 18th-century vanguard Dutch outpost, as it fought France and her Indian allies for control of the lucrative fur trade.