In the military science of fortification, wire obstacles are defensive obstacles made from barbed wire, barbed tape or concertina wire. They are designed to disrupt, delay and generally slow down an attacking enemy. During the time that the attackers are slowed by the wire obstacle they are easy to target with machine gun and artillery fire. Depending on the requirements and available resources, wire obstacles may range from a simple barbed wire fence in front of a defensive position, to elaborate patterns of fences, concertinas, "dragon's teeth" and minefields hundreds of metres thick.
A snow-covered obstacle with concertina wire
Juno Beach on D-Day, 1944. The barbed wire fence is crude and not very high. However, when combined with the steep, curving sea wall it slows down any attacker, giving time for a nearby machinegun bunker (visible on the far left) to sweep the area with enfilade fire. Note the soldier in the background, forced to use a ladder.
A complex obstacle belt of low wire entanglement backed by a double apron fence. Both obstacles have movable openings that can be blocked with knife rests.
The deadly result of enfilade fire during the Dieppe Raid of 1942: dead Canadian soldiers lie where they fell. Trapped between the beach and fortified sea wall (covered with barbed wire), they made easy targets for MG 34 machineguns in a German bunker. The bunker firing slit is visible in the distance, just above the German soldier's head.
Barbed wire, also known as barb wire, is a type of steel fencing wire constructed with sharp edges or points arranged at intervals along the strands. Its primary use is the construction of inexpensive fences, and it is also used as a security measure atop walls surrounding property. As a wire obstacle, it is a major feature of the fortifications in trench warfare.
Close-up of a barbed wire
Roll of modern agricultural barbed wire
An early handmade specimen of Glidden's "The Winner" on display at the Barbed Wire History Museum in DeKalb, Illinois
A rangeland fence which has caught a tumbleweed