A nuclear war is an armed conflict in which nuclear weapons are used, meaning explosions that release an immense amount of nuclear energy.
These weapons are extremely destructive and can cause massive devastation, both in terms of human lives and infrastructure. The effects of a nuclear war include explosions, nuclear radiation, fires, radioactive fallout, and environmental contamination.
Due to the large number of nuclear weapons in existence, a nuclear war could have catastrophic consequences globally, affecting not only the countries involved but also all of humanity and the planet as a whole.