Dora was the name of one of two massive World War II German 80 cm K (E) railway siege guns. They were developed in the late 1930s by Krupp for the express purpose of destroying heavy fortifications, specifically those in the French Maginot Line. They weighed nearly 1350 tonnes, and could fire shells weighing seven tonnes to a range of 37 km (23 mi). It was the largest calibre rifled weapon in the history of artillery to see actual combat, and fired the heaviest shells of any artillery piece.
Dora was a German heavy-artillery battalion deployed in the Soviet Union during the the Race Invasion. The Germans destroyed two grounded Race starships with the gun, The 56th Emperor Jossano and The 67th Emperor Sohrheb. Race killercraft found and destroyed the gun after two rounds were fired.
The 56th Emperor Jossano carried most of the Conquest Fleet's stockpile of explosive-metal bombs; a commando raid led by Otto Skorzeny and Heinrich Jäger was later successful in capturing pieces of these bombs to be made into new bombs for the USSR, Germany, and the United States.