In the military science

Military science

Military science is the process of translating national defence policy to produce military capability by employing military scientists, including theorists, researchers, experimental scientists, applied scientists, designers, engineers, test technicians, and military personnel responsible for...

 of fortification

Fortification

Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...

, wire obstacles are defensive obstacles made from barbed wire

Barbed wire

Barbed wire, also known as barb wire , is a type of fencing wire constructed with sharp edges or points arranged at intervals along the strand. It is used to construct inexpensive fences and is used atop walls surrounding secured property...

, barbed tape or concertina wire

Concertina wire

Concertina wire or Dannert Wire is a type of barbed wire or razor wire that is formed in large coils which can be expanded like a concertina. In conjunction with plain barbed wire and steel pickets, it is used to form military wire obstacles....

. They are designed to disrupt, delay and generally slow down an attacking enemy. During the time that the attackers are slowed down by the wire obstacle (or possibly deliberately channelled into killing zones) they are easy to target with machinegun and artillery fire. Depending on the requirements and available resources, wire obstacles may range from a simple barbed wire fence

Fence

A fence is a freestanding structure designed to restrict or prevent movement across a boundary. It is generally distinguished from a wall by the lightness of its construction: a wall is usually restricted to such barriers made from solid brick or concrete, blocking vision as well as passage .Fences...

 in front of a defensive position, to elaborate patterns of fences, concertinas, "dragon's teeth

Dragon's teeth (fortification)

Dragon's teeth are square-pyramidal fortifications of reinforced concrete first used during the Second World War to impede the movement of tanks and mechanised infantry...

" and minefields

Land mine

A land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....

 hundreds of metres thick.

One example is "low wire entanglement", which consists of irregularly placed stakes that have been driven into the ground with only some 15 cm (six inches) showing.