Fortification (obstacles)

thumb|Roman caltrop at the Westphalian Museum of Archeology (German: Westfälisches Museum für Archäologie), Herne, North Rhine-Westphalia, Germany

medieval defensive obstacle

booby trap consisting of a pit with a sharpened stake at the bottom

type of barbed wire or razor wire, formed in large coils

thumb|300px|A Cointet-element on a beach, rigged with explosive "sausages" by an American Underwater Demolition Team. thumb|300px|Cointet-element at Colleville-sur-Mer The Cointet-element, also known as a Belgian Gate or C-element, was a heavy steel fence about wide and high, typically mounted on concrete rollers, used as a mobile anti-tank obstacle during World War II. Each individual fence element weighed about and was movable (e.g. with two horses) through the use of two fixed and one rotating roller. Its invention is attributed to a French colonel (later general), Léon-Edmond de Cointet d

defensive obstacles made from barbed wire

type of military fortification