German WWI "Langer Max" 38cm SKL/45 emplacement

The 38 cm SK L/45 "Max",

also called Langer Max was a German long-range, heavy siege and coast-defense gun used during World War I. Originally a naval gun, it was also adapted for land service when it became clear that some of the ships for which it was intended would be delayed and that it would be very useful on the Western Front.

The first guns saw service in fixed positions, but the lengthy preparation time required for the concrete emplacements was a severe drawback and a railroad mount was designed to increase the gun's mobility. The latter variants participated in the 1918 German spring offensives and the Second Battle of the Marne.