Part of Operation Upshot-Knothole, was a 15-kiloton test fired from a 280-mm cannon on May 25, 1953 at the Nevada Proving Grounds. Frenchman's Flat, Nevada - Atomic Cannon TestHistory's first atomic artillery shell fired from the Army's new 280-mm artillery gun. Hundreds of high ranking Armed Forces officers and members of Congress are present. May
‘Doomsday Clock’ Ticks Forward: Climate Change, Nuclear Weapons Push Humanity Closer To Global Catastrophe
‘Doomsday Clock’ now at three minutes to midnight.