The B-52G Broken Arrow incident it occurred on January 17, 1966, over the Mediterranean Sea more precisely over Palomares, Spain, is one of the more prominent examples of a Broken Arrow incident.
The incident involved a U.S. Air Force B-52G Stratofortress bomber carrying four nuclear bombs colliding with a KC-135 tanker aircraft during a mid-air refueling operation.
It results in accidental release of nuclear weapons, and it underscored the risks associated with the storage and transportation of nuclear munitions during the Cold War era.