Internal structure of the LHC. These tubes (upper centre and bottom) contain the complex circuitry of the LHC (large hadron collider) at CERN (the European particle physics laboratory) near Geneva, Switzerland. The LHC is a 27-kilometre underground ring of superconducting magnets housed in this pipe-like structure (left and right), or cryostat. The cryostat is cooled by liquid helium to keep the operating temperature at just above absolute zero. The LHC works by accelerating two counter- rotating proton beams to an energy of 7 tera electron volts (TeV). It then forces these beams to collide head-on near two main detectors, known as the CMS (Compact Muon Solenoid) and ATLAS (A Toroidal LHC Apparatus), which detect the sub- atomic particles resulting from the collision. The LHC is scheduled to start operating in May 2008.