Booby trap
In warfare, a booby trap is an antipersonnel device, such as a landmine or grenade, placed in building or in a noncombat area that has a psychological draw for enemy soldiers. The term comes from the implication such a trap will be set off by a foolish person (a booby). The first use of the term is from the 1850s, when it was first used to describe practical jokes that are set off by their victim. In fact, the term is still used to describe a type of firework which explodes loudly when strings protruding from either end are pulled, and which is often tied to door handles and the like. A common misunderstanding is that the term comes from traps used by fishermen and sailors short on fresh meat to catch seabirds, specifically the Booby.
A booby trap is distinguished from a land mine by the fact that it is an improvised weapon, perhaps made from an artillery shell, or a grenade, or a quantity of high explosives, whereas a land mine is manufactured for its specific purpose. A booby trap may be buried in the manner common with land mines, or not, though as a rule it is concealed in some fashion, and set to be detonated by means of pressure or a trip wire. During World War II retreating British and Canadian soldiers in France in 1940 made booby traps from artillery and mortar shells, burying them in roads behind them as they retreated, or hanging them from trees concealed by the leaves and rigged with tripwires concealed in the grass around the tree.
Booby traps can also be applied as defensive weapons against unwelcomed guests or against non-military trespassers, and some paranoid people set up traps in their homes to keep people from entering. These civilian booby traps might use a non-lethal method, such as a strong electric shock, rather than explosives. As laws vary, the creator of the trap can sometimes be immune from prosecution since the victim is technically trespassing or may be held strictly liable for injuries caused to the trespasser. In some jurisdictions some types of traps are specified as illegal. Such traps have also been known to injure or kill the person setting the trap. Criminals, especially those manufacturing illegal drugs, often set these to deter law enforcement and inquisitive civilians.
A booby trap does not necessarily incorporate explosives in its construction, though they commonly do. Massive objects, such as a heavy log, or a boulder, arranged in such a manner as to fall down and crush the unfortunate person who disturbs the trigger mechanism, are also booby traps. So is a concealed pit with sharpened stakes in the bottom (often referred to as Punji sticks). Perhaps the best book about boobytraps is US Army's FM 5-31 Boobytraps.
Usage throughout history
Winter war
During the Winter War between Finnish and Soviet forces, Finnish guerrilla fighters would modify dud Soviet bombs to be improvised anti-tank and personnel mines. The modified bombs were buried with the trigger exposed in roads, so that they were activated by a passing tank.
WWII
During World War II, scales in warehouses and factories were rigged with explosives. Allied soldiers securing an area would be tempted to step upon the scale to compare their weight with that of their compatriots, and would thus perish.
During the Warsaw Ghetto Uprising, Jewish resistance fighters severely worsened Nazi casualties through a vast array of improvised and often elaborate booby traps, set up inside the ghetto buildings and basements. They were so effective that the German forces eventually decided to demolish every building systematically rather than risk entering.
Cold War
During the Soviet era in Eastern Europe, the Warsaw Pact attempted to better secure their borders with Western Europe by rigging border fences sporadically with explosive devices. These were usually fairly simple devices, often no more complicated than landmines hung on barbwire. The mines were modified to be sensitive enough to go off if the barbwire was tampered with or cut.
During the Vietnam War, motorcycles were rigged with explosives by the NLF and abandoned. US soldiers would be tempted to ride the motorcycle and thus trigger the explosives. As well, NLF soldiers would rig Rubber Band Grenades and place them in huts that US soldiers would likely torch. Another popular booby trap is the Grenade in a Can trap. This involves a primed grenade in a container and a string attached, sometimes with the grenade's fuse mechanism modified to give a much shorter delay than the four to seven seconds typical with grenade fuses. The NLF soldiers primarily used these on doors and attached them to tripwires on jungle paths.
The NLF also used far simpler, but also effective, low technology booby traps in the form of punji sticks hidden in pits.
Middle East
During the Al-Aqsa Intifada, Palestinian fighters used booby traps widely. The largest use of booby traps was in Jenin during Operation Defensive Shield where a large number of explosive devices were planted.
The Palestinian fighters had made their own preparations. Booby traps had been laid in the streets of both the camp and the town, ready to be triggered if an Israeli foot or vehicle snagged a tripwire. Some of the bombs were huge—as much as 250 lb (110 kg) of explosives.