Ground That Fights Back: Obstacles, Mines and Traps

Start with the oldest idea on the path: a conical pit about 2 meters deep with a sharpened stake at the bottom. Julius Caesar described the pits at the siege of Alesia, where his soldiers called them lilies, and Roman examples survive at Rough Castle on the Antonine Wall.

Several sharp spikes arranged so that one point always faces up, strewn to injure the feet of horses, war elephants and camels. The Roman writer Vegetius described soldiers scattering them against scythed chariots and cavalry, and drones have dropped caltrop-like devices to disable vehicle tires in Ukraine.

The Japanese version of the caltrop, made as iron tetsubishi or from dried water caltrop seed pods. Its points could pierce the straw waraji sandals of the period, and it could be thrown like a shuriken as well as scattered on the ground.

A sharpened bamboo or wooden stake hidden in a pit or beside a path, often smeared with poison so that infection did the work. The British Indian Army met the trap among the Kachin people on the Burma frontier in the 1870s, and it became a symbol of guerrilla war in Vietnam.

The first United States patent went to Lucien B. Smith in 1867 and Joseph Glidden patented the dominant form in 1874. Strung in dense entanglements, it channeled First World War infantry into machine-gun fire until tanks broke through it, most decisively at Amiens on 8 August 1918.

Barbed or razor wire coiled so that it expands like a concertina and needs no posts. The modern self-supporting design came from the German engineer Horst Dannert in the 1930s, and a small unit can lay roughly a kilometer of it in an hour.

The engineer's answer to wire and mines: a charge in connected tubes pushed forward from cover. Captain R. L. McClintock of the Royal Engineers devised it in British India in 1912, and it cleared wire at Cambrai in 1917 and has stayed in service since.

A star of crossed steel beams that keeps working even when an explosion overturns it. Major Frantisek Kasik invented it for the Czechoslovak border defenses of the late 1930s, and Ukraine revived mass production of it in 2022.

A buried answer to the new British tank, which began in the First World War as artillery shells in the ground. Germany fielded the Flachmine 17, the Soviet Union its EZ mine in 1924 and Germany the Tellermine 29 in 1929, and the tilt-rod fuze let a mine strike beneath the vehicle.

The German bounding mine, with more than 1.93 million produced between 1935 and 1945. A small charge threw it about a meter up to burst at waist height and scatter around 360 steel balls, which is why Allied troops feared the Bouncing Betty.

The mine made for people rather than vehicles, in blast and fragmentation families. Doctrine often favored wounding over killing, because a wounded soldier draws more of the enemy's medical and logistical resources than a dead one.

A device triggered by the victim's own presence, striking whoever springs it. The military sense dates to the First World War, and later examples include Viet Cong traps and the Operation Project Eldest Son response, bombs of the Troubles in Northern Ireland, and the traps laid at Jenin in 2002.

A bomb built and placed outside conventional military manufacture. The British Army coined the term in Northern Ireland, it passed into wide American use during the Iraq War, and the same idea appears centuries earlier as the fougasse and in the Belarusian Rail War of 1943 and 1944.

The modern end of the path, a weapon that releases submunitions, sometimes more than two thousand, over a wide area. The first operationally significant one was the German SD-2 Butterfly Bomb of the Second World War, and from the 1970s at least thirty-four countries fielded them.