Either of two different sets of long-range artillery produced by the Krupp works (see Thyssen Krupp Stahl) in Germany during World War I. The first were 420-mm (16.5-in.) howitzers used by German forces advancing through Belgium in 1914. The second were cannons specially built to bombard Paris in 1918. About 112 ft (34 m) long, they weighed 200 tons (181 metric tons) and were 210 mm (8 in.) or more in calibre. The Paris guns were moved on railway tracks; they bombarded the city for 140 days. Their unprecedented range of 75 mi (121 km) was achieved by sending the shells on a trajectory 12 mi (19 km) into the stratosphere. They were nicknamed for the Krupp matriarch Bertha von Bohlen