The United States has lost at least three nuclear bombs that have never been located, and they remain missing to this day. These incidents occurred during the Cold War, a period when the US kept armed aircraft in the sky at all times as part of Operation Chrome Dome. The bombs are believed to be hidden in swamps, fields, and oceans across the globe.
One of the most famous cases is the Palomares incident in Spain on January 17, 1966. Two US military planes collided mid-air, scattering four B28 thermonuclear bombs. Three were quickly recovered on land, but one fell into the Mediterranean Sea and has never been found. The missing bomb carried a 1.1 megatonne warhead, equivalent to 1,100,000 tonnes of TNT.
There have been at least 32 'broken arrow' accidents involving nuclear weapons since 1950, according to declassified US Department of Defense documents. However, experts say the full extent of such incidents is unknown, particularly for other nations like the UK, France, Russia, and China. The Soviet Union also lost nuclear bombs, but those were on submarines and their locations are known, though inaccessible.
One Soviet incident occurred on April 8, 1970, when a fire broke out on the K-8 nuclear submarine in the Bay of Biscay. The submarine sank with four nuclear torpedoes onboard. In 1968, another Soviet submarine, the K-129, sank in the Pacific Ocean with its nuclear cargo. These lost vessels highlight the ongoing risks associated with nuclear weapons.
