Season 4

Puzzles involving the Chisholm Trail, Houdini posters and a flag that may have draped the coffin of President William McKinley, assassinated in 1901. Included: determining how far south the Chisholm Trail extended; checking the authenticity of Harry Houdini posters for a Chicago magic show; learning if a flag handed down to the great-grandson of McKinley's bodyguard actually adorned the 25th president's casket.

Questions surrounding a baseball autographed by Dizzy Dean, a brass eyeglass containing an image of Jefferson Davis, and a question on credit for an oil-drilling device. Included: investigation of a 1944 baseball game in which the players supposedly included Dean, Satchel Paige and an Air Force staff sergeant; whether an eyeglass belonged to a Confederate supporter; whether a twin-cone roller-rock bit was invented by Howard Hughes or a San Jose resident's grandfather.

Puzzles involve an 1886 Coca-Cola trade card, a map connected to a Civil War battle and a billy club from a 1912 textile-factory strike in Lawrence, Mass. Included: a trip to Coca-Cola headquarters in Atlanta to try to verify the trade card info; digging up details pertaining to the 1863 siege of Vicksburg, Miss.; a journey to Lawrence to investigate the Bread and Roses strike.

Puzzles pertaining to 1943 certificates labeled “alternate service to war”; a set of books that may have belonged to 19th-century politician John C. Calhoun; and a toy mouse named Micky that bears a patent date of 1926 (two years before Walt Disney created Mickey).

Puzzles concerning items believed to have come from a WWII kamikaze attack; a badge that may have belonged to a British soldier in the Revolutionary War; and two New Jersey brothers who suspect that their uncle built the Spirit of St. Louis's Wright Whirlwind J-5C engine.

Puzzles involve a film reel of 1920s stuntman Eddie Polo; scales used by Chinese immigrants in the early 20th century; and a shotgun that belonged to Nazi henchman Hermann Goering.

Puzzles involve a camera that belonged to a Holocaust survivor; the link between a 1942 letter and the early days of Alcoholics Anonymous; and a cross found at a Tallahassee excavation of a 17th-century mission.

Puzzles include a bison skull that may date to 3000 B.C.; a watch that may have belonged to gambler-gunman Doc Holliday; and stock certificates possibly signed by black nationalist Marcus Garvey.

Puzzles involve a car that may be the one driven by Grace Kelly in “To Catch a Thief”; possible Civil War POW photographs; and a 1914 motorcycle that might have been used in WWI France.

A baseball ticket possibly signed by Lou Gehrig on the day of his farewell speech; an electric streetcar from Cleveland; and a document that may have granted freedom to a slave.

A Superman sketch apparently signed by the comic strip's creators; a metal master used to press records in the 1920s and '30s; and a whiskey flask that may date to the time of George Washington.