Nuclear artillery test Grable Event - part of Operation Upshot-Knothole, a 15-kiloton test fired from...

The M65 or T-131 (nicknamed Atomic Annie, in Germany also Atom-Anni or Atomkanone) was a heavy nuclear-capable artillery gun caliber 280 mm of American production. History'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. The fireball ascending. Grable is next to Priscilla the only example of a double-layer cloud with a fire ring. The smoke trails at the front of the image derived from missiles that were fired shortly before detonation, to investigate the invisible pressure wave.