Yellow button with black text and the image of an orange smiling sun in the middle.
1978 DONNELLY/COLT BUTTONS Box 271. New Vernon N.J.07976 For Catalog write: EARS, 2239 East Colfax Denver, Co. 80206
The Smiling Sun is the international symbol of the anti-nuclear power movement. It was designed by anti-nuclear activists, Anne Lund and Soren Lisberg, for Denmark's OOA (Organization for Information on Atomic Energy) in 1975. Smiling Sun buttons were originally passed out at the May 1st celebration in Arhus Denmark, but soon were used by anti-nuclear activists around the world, with the words "Nuclear Power? No Thanks" translated into over 40 languages. This message was designed to be polite and friendly, but firm, and to encourage dialog. The sun was chosen as a symbol of hope because it sustains life on earth. The button is yellow because shops in Denmark use black letters on a yellow background for their signs, so Lund and Soren felt it was a welcoming color.
Sources: Bardi, U. (2011 April 10). Interview with the designer of the "Nuclear? No Thanks" logo [weblog post]. Cassandra's Legacy.
OOA Fonden. (2007). Smiling sun history.