World War III

World War III (abbreviated as WWIII or WW3) or the Third World War is a hypothetical future global conflict subsequent to World War I (1914–1918) and World War II (1939–1945). It is widely assumed that such a world war would involve all the great powers, like its predecessors, and include the use of nuclear weapons or other weapons of mass destruction, and thus surpass prior conflicts in geographic scope, destruction, and loss of life.

Since the Manhattan Project's development of nuclear weapons in 1945 and their use by the United States in the atomic bombings of Hiroshima and Nagasaki at the end of World War II, the risk of a nuclear apocalypse causing widespread destruction and the potential collapse of civilization or extinction of humanity has become a common theme in speculation and fiction about World War III. With the advent of the Cold War (1947–1991) and spread of nuclear weapons to the Soviet Union, followed by their acquisition by several other countries, the risk of a third world war increased. During the Cold War, this possibility was anticipated and planned for by military and civil personnel in various countries, with scenarios ranging from conventional warfare to limited or total nuclear warfare, and the doctrine of mutually assured destruction (MAD), which determined that a full-scale nuclear confrontation would completely annihilate all parties to the conflict, was developed. U.S. and Soviet leaders worked to avoid such an outcome, though several near-misses, caused by faulty technology or human error, still occurred, underscoring the need for restraint by both sides.

Various military conflicts which have occurred since the beginning of the 21st century, most notably the Russian invasion of Ukraine since 2022, as well as rising geopolitical tensions between the United States and China, have been perceived as potential flashpoints or triggers for a third world war.^[1][2]