From Wikipedia: The Atomium is a monument built for Expo '58, the 1958 Brussels World's Fair. Designed by André Waterkeyn, it is 102-metres (335 ft) tall, with nine steel spheres connected so that the whole forms the shape of a unit cell of an iron crystal magnified 165 billion times. Tubes which connect the spheres along the 12 edges of the cube and all eight vertices to the centre enclose escalators connecting the spheres which contain exhibit halls and other public spaces. The top sphere provides a panoramic view of Brussels. Each sphere is 18 metres in diameter. The vertical vertex contains a lift which was considered very fast and advanced at the time of building (the speed is 5 m/s).