Atomium

The Atomium still provokes the same argument it caused in 1958: to its designers it was a tribute to the peaceful atom, a glowing promise of nuclear energy serving humanity; to its critics it was an extravagant stunt. What neither side disputed was that engineers Andre Waterkeyn and the Polak brothers had built something structurally audacious, nine spheres of 18-inch steel tubing connected at angles that required precision engineering across five years of development. The structure is 335 tonnes of steel and each sphere is 18 metres in diameter, roughly the volume of a small apartment building.

The central sphere sits 92 metres above the base plate and houses a panoramic terrace reachable by one of the original Otis escalators, still operating and still an experience in themselves — long, steep, and slightly disorienting as they rise inside the narrow vertical tube that connects the spheres. The top sphere's view over the Brussels suburbs and the distant tower blocks of the EU district makes the geometry of the building legible from above: what looks like a random arrangement of tubes is in fact a precise model of an iron crystal lattice magnified 165 billion times.

From the ground the scale is deceptive; the spheres appear small until you notice the maintenance gantry at their equator, the size of a normal building's roofline. Night lighting has changed several times over the decades, and the current scheme illuminates the struts in cool blue-white that recalls both laboratory fluorescence and the cold glamour of the atomic age. The Atomium was never meant to be permanent: it was designed for a six-month Expo and the decision to keep it was made only after public affection for the structure became clear.

Inside the lower spheres are exhibition spaces that have hosted retrospectives on architecture, design, and Belgian culture. The permanent collection at ground level explains the construction process through original drawings and structural models, and a small cinema shows period footage from the 1958 Expo, when the Atomium was the only permanent structure among pavilions that were demolished after the fair closed. The surrounding Heysel Plateau also houses Mini-Europe, whose scaled models of EU landmark buildings draw families in summer, and the rebuilt King Baudouin Stadium.

The Atomium gives you both a lesson in mid-century optimism about science and a peculiar object that looks like nothing else on earth. Whether you find it beautiful or merely strange depends on your relationship with the aesthetic of the 1950s, but it is impossible to deny that it occupies a unique place in the iconography of Belgium, reproduced on postcards, fridge magnets and Belgian EU presidency materials with a consistency that few other structures achieve.

It is the only major structure from the 1958 World Expo still standing, and one of the few genuinely iconic modernist landmarks in Belgium.

The engineering — nine spheres on a precise iron-crystal lattice — remains remarkable, and the escalator ascent is unlike anything else in European landmark architecture.

The Atomium gives you both a lesson in mid-century optimism about science and a peculiar object that looks like nothing else on earth.