Keywords: Upshot-Knothole Encore (1953) (cloud).jpg en Operation Upshot-Knothole ENCORE Event - Nevada Proving Ground atomic detonation on 8 May 1953 at the AEC's Nevada Proving Ground 222 UK-53-168 Federal Government of the United States PD-USGov Upshot-Knothole Encore Photographs taken on 1953-05-08 |