Atomium

The Atomium is a monument in Brussels, originally built for Expo '58, the 1958 Brussels World's Fair.

Designed by André Waterkeyn, it stands 102 metres (335 ft) tall. It has nine steel spheres connected so that the whole forms the shape of a unit cell of an iron crystal magnified 165 billion times. Tubes connect the spheres along the 12 edges of the cube and all eight vertices to the centre. They enclose escalators connecting the spheres containing exhibit halls and other public spaces. The top sphere provides a panoramic view of Brussels. Each sphere is 18 metres in diameter. Four spheres are currently (as of 2012) closed to visitors; others can be reached easily by escalators. The vertical vertex contains a lift which was very fast and advanced at the time of building (the speed is 5 m/s). The renovation includes revamped exhibition spaces, a restaurant, and a dormitory for visiting schoolchildren called "Kids Sphere Hotel" which features suspended plastic sphere towers. A €2 commemorative coin depicting the sculpture was issued in March 2006 to celebrate the renovation. The Atomium is one of the most visited attractions in Brussels today. In 2008, the Atomium celebrated its 50th anniversary, with activities planned all year, including free admission for those turning 50 between April and October. The Atomium is located on Boulevard du Centenaire, beside the King Baudouin Stadium in Heysel Park.

Three of the four uppermost spheres lack vertical support and hence are not open to the public for safety reasons, although the sphere at the pinnacle is open to the public. The original design called for no supports; the structure was simply to rest on the spheres. Wind tunnel tests proved that the structure would have toppled in an 80 km/h wind (140 km/h winds have been recorded in Belgium). Support columns were added to achieve enough resistance against overturning.