Germany Railway Cannon!!!!!!
I don't know real thickness,so its thickness is default size.
In the latter half of the 1930s, the Wehrmacht,
which had abrogated the military restrictions of the Treaty of Versailles in its rearmament declaration, commissioned Krupp, an excellent munitions company, to develop and manufacture a new type of train gun capable of attacking the Maginot fortress line built on the French border. The 80cm train gun was completed as part of this project. The two guns produced were named "Gustav" and "Dora" after Gustav Krupp, the chairman of Krupp at the time, and Mrs. Dora Muller, the wife of Erich Muller, the chief designer of the guns. Read More