Created by Engineer André Waterkeyn, and architects André and Jean Polak, for the 1958 World Exhibition, the Atomium is a landmark building inspired by the structure of an atom. To be more precise, the design is based upon the cuboid form of a unit cell of iron crystals, amplified 65 billion times to achieve a total height of 102 meters (335 feet). The nine gleaming spheres are held together by tubes, each sphere representative of one of the nine Belgian provinces. The final effect is that of a mammoth, geometric atom composed entirely of metal. The spheres are encased in stainless steel, and harbor exhibition rooms and other public spaces, while the top-most sphere hosts a restaurant with panoramic views of the city. The connecting tubes accommodate escalators, elevators, and stairways that link the individual spheres to one another.