The ITER program is the result of the commitment of 35 countries to design, build and operate an experimental thermonuclear reactor of the "tokamak" type. Occupying a 180-hectare site in Saint-Paul-lez-Durance (13), the ITER facility, whose construction began in 2010, has 39 scientific and auxiliary buildings, concentrated on a 42-hectare platform. The main building, intended to house the experimental machine - the largest and most powerful in the world - culminates at an exceptional height of 60 meters with a 13-meter basement. The architectural challenge associated with this project? It consists of erasing the impact of the imposing structures on their environment by implementing reflective cladding - here in bright annealed stainless steel - and deconstructing them via the interposition of pre-painted cladding - here in Onyx 60µ color.