A square of fabric that may have been part of an NC-4 aircraft, which was the first to fly across the Atlantic; and an altimeter that might have been part of the XF-11 aircraft flown by Howard Hughes in 1946. Also: a piece of material that may have been part of a Civil War-era hot-air balloon designed for the U.S. Army.

A saddle that may have been owned by cowboy legend Bill Pickett; a flag that might have been draped over the casket of President William McKinley; and film cans that may contain archival footage of Nazi officials.

Two bars of silver that may have been from a Spanish ship that went down off Florida; a book that might have belonged to social activist Lucy Parsons; a typewriter that may have belonged to WWII journalist Ernie Pyle.

A possible Colonial-era $6 bill found by a Nebraska family; and a British 10-shilling note said to have been signed by FDR, Winston Churchill and George Patton. Also: A North Carolina woman has a pin she claims was made from metal taken from the Liberty Bell.

The fifth season begins with a portable projection screen that may have been used by President Kennedy to view spy photos during the Cuban Missile Crisis. Also: an aluminum record that might contain an original recording of the “Amos 'n' Andy” program; and a painting that may have been an original portrait used in the women's suffrage movement.

A fight bell that may have been used in a Jack Dempsey boxing match; a photo that may depict white Civil War soldiers standing with two black men, all of whom are thought to be members of the Grand Army of the Republic. Also: a document that may have Thomas Jefferson's signature on it, along with a pledge that would help finance a school.

Movie posters for a film that might contain footage of fighting during the Mexican Revolution; and an autograph book that may have signatures from Warren G. Harding and Calvin Coolidge. Also: a robe that might have belonged to Gen. Peter Muhlenberg, who led troops during the American Revolution.

No description available

No description available

A 1932 Ford Roadster that may have been used in dry-lake races; a letter that may have been written by Mount Rushmore sculptor Gutzon Borglum to James Red Cloud of the Lakota tribe; a cast-iron eagle that might have been a decoration for a New York post office

A letter that may have been signed by Abraham Lincoln; a map that might have markings for the Underground Railroad in Ohio; and artifacts that may have been aboard the USS Indianapolis when the ship was sunk by a Japanese sub during WWII.

The fifth season ends with documents that may be related to the USS Thresher, a nuclear sub that sank in 1963; storyboards that may be for a comic strip about one-armed baseball player Pete Gray; and handwritten documents that may pertain to the Manhattan Project during World War II.