A pic of the Atomiumin in Brussels, Belgium.
This landmark was originally built in Brussels for the 1958 Brussels World's Fair, on the Heysel Plateau where it still stands. Desinged by engineer Andre Waterkeyn, and architects Andre and Jean Polak, it stands 102m (335ft) tall is now a museum. It has nine 18m (60ft) diameter spheres, covered with stainless steel, and are connected to form the shape of a "unit cell of an iron crystal magnified 165 billion times." (Wikipedia) The spheres are connected by stainless steel covered, 3m (10ft) diameter tubes that contain stairs, escalators, and a elevator (in the central/vertical tube) that allow access to the spheres. The spheres contain exhibits, a restaruant with panoramic views of Brussels, sleeping "pods" in which groups like scouts/school field trips can overnight, along with other public spaces.
This, in my opinion, was one of the coolest things/places that we did while visiting my sister in the Netherlands. This was one of several trips into Brussels, which wasn't very far from where my sister and her family were staying.