Brussels’ landmark Atomium attraction is cutting its visiting hours due to soaring temperatures that are turning the iconic steel structure into an oven.

“Due to extreme heat and the structural limitations of the building, the indoor temperature at the Atomium will be particularly high in the coming days,” said a statement on its website.

One of Belgium’s most recognizable landmarks, the Atomium is a giant model of an iron molecule — nine atoms arranged in a cube — magnified 165 billion times.

Designed for the 1958 Brussels World’s Fair (Expo 58), the building was not designed with extreme heat in mind. Its distinctive stainless-steel spheres absorb and retain heat, making the interior uncomfortably warm during high temperatures.

The Atomium is opening at 10 a.m. and closing at 2:30 p.m. until Wednesday, with last entry at 1 p.m. The statement said that visitors who have already purchased tickets online can reschedule their visit anytime throughout 2025.

This marks only the second time that the attraction has reduced its hours due to heat, the first being in 2019.

Belgium, like much of the rest of Europe, is sweltering this week, with Belgium’s Royal Meteorological Institute issuing an orange alert for Tuesday and Wednesday as temperatures climb toward 37 C.

In Brussels, authorities have rolled out heat-mitigation measures to protect vulnerable groups. Crèches without air conditioning may temporarily close; outreach teams are distributing water to the homeless; and social workers are checking in on elderly residents.