This bookmark represents one of the most famous designs of the twentieth century. It was a massive engineering feat built in Brussels for the 1958 World's Fair or Expo 58. The Atomium was the main pavilion and icon of the fair, and represented "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."It is an elementary iron crystal enlarged 165 billion times. It has nine interconnected spheres that could be entered with exhibits in them. It is still open to the public, and you can even "fly" from the top sphere. Submitted by Lauren Roberts.