The Atomium, Heysel, Belgium.
"The Atomium ( // ə-toh-mee-əm) is a building in Brussels originally constructed for Expo 58, the 1958 Brussels World's Fair. Designed by the engineer André Waterkeyn and architects André and Jean Polak, it stands 102 m (335 ft) tall. Its nine 18 m (59 ft) diameterstainless steel clad spheres are connected so that the whole forms the shape of a unit cell of aniron crystal magnified 165 billion times. The name is a combination of atom and aluminium. It is a museum. 
Tubes of 3 m (9.8 ft) diameter connect the spheres along the 12 edges of the cube and all eight vertices to the centre. They enclose stairs, escalators and a lift (in the central, vertical tube) to allow access to the five habitable spheres which contain exhibit halls and other public spaces. The top sphere includes a restaurant which has a panoramic view of Brussels. CNN named it Europe's most bizarre building."