This model of an iron crystal unit cell magnified billions of times symbolically represents the peaceful use of nuclear energy. Originally there was even a nuclear reactor under it.
The 102-meter-tall (335-foot) Atomium was constructed for the 1958 Brussels World Fair. The nine spheres, some of which can be walked through, contain exhibits and offer 360-degree panoramic view of the Belgian capital. To reach the spheres, visitors take a ride in what the site calls Europe's fastest elevator (5 meters/second). The landmark is topped off with a restaurant at dizzying height of 100 meters.