5921481 Challenger tank, Holland, 17 October 1944 (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: Challenger tank (A30), Holland, 17 October 1944. Photograph, World War Two, North West Europe (1944-1945), 1944. The Challenger was based on the chassis of a Cromwell tank with a new turret designed to house a heavier 17-pounder gun. It was also armed with a Browning .30 inch machine gun. The 17-pounder was capable of penetrating the armour of any Axis tank.); by National Army Museum ; out of copyright.