Claim: Heldsberg, overlooking the Rhine (second-longest river in Central and Western Europe), was armed with four 75mm guns, mounted in individual concrete blockhouses, and supported by five machine gun blocks with a total of seven machine guns in between.
Evidence: It is the second-longest river in Central and Western Europe (after the Danube), at about 1,230 km (760 mi), with an average discharge of about 2,900 m/s (100,000 cu ft/s). Heldsberg was armed with four 75mm guns, mounted in individual concrete blockhouses, supported by five machine gun blocks, divided into north and south batteries. A total of seven machine guns were provided, distributed between the dedicated machine gun blocks and the artillery blocks.