The Atomium is a museum in Brussels (Belgium) originally constructed for Expo 58, the 1958 Brussels World's Fair. Designed by the engineer André Waterkeyn, it stands 102 m (335 ft) tall. Its nine 18 m (59 ft) diameter stainless steel clad spheres are connected so that the whole forms the shape of a unit cell of an iron crystal magnified 165 billion times.