Mounting heavy artillery on mobile railroad cars was first proposed by Russian Gustav Kori in 1847, and was first used in combat in the American Civil War.

When World War I began, France and Germany appropriated naval cannons and coastal defense batteries and deployed them to the front via rail.

Once in place, railway guns were mounted on specially constructed semicircular tracks, which allowed them to be pointed in the direction of targets.

In World War II, Germany built the utterly massive Schwerer Gustav gun, which could fire 31-inch, seven-ton shells and hit targets up to 30 miles away.

As these guns were hugely expensive and vulnerable to air attacks, after World War II they were phased out in favor of bomber aircraft and surface-to-surface missile launchers.

These photographs span the history of railway guns, from the very first used by Confederate forces in the American Civil War, to Autochrome photos of guns on the western front of World War I, to then near-obsolete behemoths of World War II.