Atomium

   A giant replica of an iron molecule built for the World's Fair of 1958 that has become an identifying symbol of Brussels, the Atomium's nine aluminum-coated steel spheres represent the atomic structure of the molecule magnified 165 billion times. Designed by engineer André Waterkeyn, who spent four years planning and constructing it, the edifice was intended to mark the arrival of the atomic age in serving as both a symbol of scientific progress and a monument to the peaceful application of atomic energy.

   The Atomium, built on the Heysel plateau, rises 102 m (332 ft.) above the boulevard du Centenaire and weighs 2,400 tons. The nine spheres, each measuring 18 m (59 ft.) in diameter, represent the nine Belgian provinces in 1958 (there are 10 since 1 January 1995). The spheres are connected by tubes running 29 m (94 ft.) in length and 3 m (10 ft.) in diameter, and they are each divided into two storeys. An elevator that runs through the central tube connects the bottom sphere with the top one in 23 seconds and escalators link the surrounding spheres. At night, the nine spheres are illuminated by small lights. Switched on alternately, the lights revolving around the sphere illustrate the movement of electrons around an atomic nucleus.

   The Atomium was refurbished in 1993. The structure is thermally insulated, soundproofed, and air conditioned, and it is flexible, allowing it to move with the wind for safety reasons. Space is available for exhibitions and a restaurant and observation deck are located in the top sphere. The structure was closed again in 2004 for restoration.