This card depicts the "Atomium", the symbol of Expo 58, the 1958 World's Fair in Brussels, the first such fair since World War II. As described on the Atomium's website, the structure "symbolised the democratic will to maintain peace among all the nations, faith in progress, both technical and scientific and, finally, an optimistic vision of the future of a modern, new, super-technological world for a better life for mankind. The peaceful use of atomic energy for scientific purposes embodied these themes particularly well and, so, that is what determined the shape of the edifice." The structure is 102 metres high and represents an elementary iron crystal. Engineer André Waterkeyn and architects André and Jean Polak contributed to the design. Although intended to be disassembled after the fair, the Atomium has survived and been refurbished, much like other exposition icons like the Eiffel Tower and the Unisphere from the 1964-65 New York World's Fair.
Among the national and industrial exhibits at the fair (I love that there were pavilions for chocolate - after all this is Belgium -- and tobacco), Westinghouse had an exhibition which included a model reactor, depicted on this card. On the reverse the card states that the reactor will be completed between 1960 and 1962, and will be used at the Yankee plant in the U.S. (Yankee Rowe in Massachusetts) and the SELNI plant in Italy .