Pride of the Washington Navy Yard’s outdoor ordnance museum, the railroad gun is a monument to the combination of technical ingenuity and colossal excess that humanity is capable of throwing into military conflicts.

The railroad gun is the last of five that the United States built during World War I to pummel German trenches from afar. The land-Dreadnought boasts a monstrous 14-inch diameter gun that can rain down shells on targets 20 miles away. The size and weight of the contraption, along with France’s wrecked road network, meant that rails were the only practical way to bring the hulk anywhere approaching the front lines.

Railroad guns are a specimen of the unique military forces at play in World War I that turned the Western Front into a protracted two-way siege. Generals on both sides came to the field with weaponry far more advanced than their tactical methods of fighting, leading to four years of stagnation and overkill.

This particular railroad gun fired its last salvo on Nov. 11, 1918. Today it watches over the Washington Navy Yard, well positioned in the event of an Imperial German Navy probe up the Potomac River. The only other place to see a railroad gun in the United States is at the Aberdeen Proving Ground, which has a captured German Krupp gun.