Apart from Manneken Pis the Atomium is Brussels' best-known attraction. Planned by the architect André Waterkeyn for the 1958 Brussels World Exhibition, the 326 feet high steel and aluminum construction symbolizes a molecule of iron magnified 165 million times. Four of the nine spheres are now used for the presentation of a show about human life called "Biogenium". These 9 spheres are linked by 20 tubes, the whole resting on 3 pillars. This unique piece of architecture, fashioned on the occasion of the World Fair of Brussels in 1958, became the most popular testimonial of the capital of Europe.