In 1935, the Maginot Line was one of the military objectives of prime importance for the German Army. To achieve a solution to the problem of the neutralization of such an exceptional defensive position of the potential adversary it was decided to research a weapon in the genre of the Bertha super cannon, which in the First World War had bombarded Paris with optimal results. The specifications indicated were: range, 35-45 kilometers; maximum elevation, 65 degrees; penetration, one meter of steel armor or seven meters of reinforced concrete or 30 meters of compact terrain. The company which managed to present the project of a weapon which fulfilled such requirements was once again Krupp, with a team of technicians led by Engineer Erich Muller. The result of the research was a gigantic cannon installed in a railway carriage supported by four platform wagons, which remained disassembled in a depot and was assembled each time in the site of utilization. The ensemble was moved by two Diesel locomotives of 1000 horsepower each. The elevation and the reload were electrically operated, whereas for the horizontal orientation it was necessary to build a large platform with a curved railway on which the cannon was moved until achieving the desired position (as shown in the drawing). At least three trains were needed to transport the materials, with almost 1000 specialists. For the construction of the artillery position it was provided the employment of about 1500 workers who were recruited on the place. The facilities, commanded by a Colonel Engineer, comprised the General Headquarters, a section for fire control, another one for security service and another one for emergency and service personnel; about 500 men in total. As support and protection, apart from the technical personnel, they were provided a Flak detachment and another one of Nebelwerfer, 20 engineers from Krupp, two guard companies, a military police unit with dogs and a section of the Luftwaffe for aerial cover and reconnaissance; almost 3870 men in total. For firing the cannon 350 men were necessary. The maximum shot dispersion was one percent. Due to the war events the "Dora" was never used in France, but it was used to neutralize the fortifications of Sevastopol by effectuating 48 shots in five days. It would be later used in 1944, during the uprising in Warsaw.