The Rodman gun, from Fort Pitt Foundry, en route to Fort Hamilton, New York

Produced at Fort Pitt Foundry in 1864, this massive 20-inch caliber gun, the largest ever cast, was made possible through an innovative process pioneered by ordnance expert Thomas Jackson Rodman. Designed for seacoast fortifications, Rodman guns once guarded entry to New York harbor. An engineering marvel of its day, the 20-caliber Rodman gun inspired author Jules Verne’s conception of a cannon that could shoot men into space in From the Earth to the Moon (1865).