The Atomium resembles the shape of an unit cell of an iron crystal, magnified 165 billion times. It was built for the World Expo of 1958 and measures a near 100 meter in height. The Atomium was not intended to survive beyond the 1958 World Fair but its popularity and success soon made it a key landmark, first of Brussels then internationally. Its nine interconnected steel spheres can be visited by escalators, with the top sphere providing a panoramic view of Brussels.