Who ran the company that produced the largest pieces of artillery used during World War I by barrel length?
Gustav Krupp von Bohlen und Halbach: Gustav Krupp von Bohlen und Halbach (7 August 1870 – 16 January 1950) ran the German Friedrich Krupp AG heavy industry conglomerate from 1909 until 1941. Gustav Krupp von Bohlen und Halbach:  Krupp produced the Tiger I tank, Big Bertha, the Paris Gun, among other inventions under Gustav.
i don't know