A portrait created in a German prisoner of war camp; the Seadrome, a floating airport anchored to the ocean floor where trans-Atlantic passenger flights could refuel; and an intact artillery shell that may have been part of an attack on the U.S. in WWI.

Stalag 17 Portrait - A Tempe, Arizona, woman has an intriguing memento of a sobering World War II experience: a portrait of her father sketched while he was held inside the German prisoner of war camp, Stalag 17B. On the back, her father has noted: "Done in May of 1944 by Gil Rhoden, using a #2 lead pencil. We were POWs in Stalag 17 at Krems, Austria. Gil agreed to do my portrait in exchange for two onions and a small potato." What happened to the artist? Did he survive the camp? HISTORY DETECTIVES guest host Eduardo Pagán uncovers a stoic act of defiance and dignity behind the Stalag's barbed wire.

Seadrome - A Rochester, New York, man inherited three photos of a Seadrome model from his grandfather. More than a decade before Charles Lindberg made his solo non-stop flight across the Atlantic, an American engineer proposed the Seadrome, a floating airport anchored to the ocean floor where trans-Atlantic passenger flights could refuel. HISTORY DETECTIVES host Tukufu Zuberi travels to New York, Delaware and Maryland to find out what happened to this fantastic engineering marvel and discover what role the contributor's grandfather played in the Seadrome's history.

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.