The LHC, the biggest experimental device ever built, runs few kilometres from Geneva, in Switzerland. It is conceived to understand how the universe agglomerated, particles’ physicists, at an international scale, experiment there the most advanced theories in physics about the origin and becoming of the world. Located at one hundred meters underneath, therefore invisible in the landscape, this extraordinary machine is, on the ground, the very focal point of multiples attentions and is subject to endless measures. Because of what it is aimed at (the Big Bang, Black Holes, Antimatter…), as well as because of its size and its territorial footprint, the LHC nourishes several disaster scenarios that the CERN has to neutralise as soon as they show up by using heterogeneous methods: among them, technical measures, legal norms or monitoring of the environment.