A closeup of the fireball and mushroom cloud from the Upshot-Knothole Grable atomic bomb.
Source: This image is available from the National Nuclear Security Administration Nevada Site Office Photo Library under number XX-12. This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. http://en.wiktionary.org/wiki/File:Uk-grable2.jpg
Author: Federal Government of the United States