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Founded in 1954, the European Organisation for Nuclear Research, 8km west of Geneva, is a laboratory for research into particle physics. It accelerates protons down a 27km circular tube (the Large Hadron Collider, the world's biggest machine) and the resulting collisions create new matter. Two exhibitions shed light on its work and two-hour guided tours in English delve deeper; reserve online up to 15 days ahead and bring photo ID. From the train station take tram 18 (Sfr3, 20 minutes).