The Large Hadron Collider or LHC is the world’s largest and highest-energy particle accelerator. Built by the European Organization for Nuclear Research (CERN) with the intention of testing various predictions of high-energy physics, it lies in a tunnel beneath the Franco-Swiss border near Geneva, Switzerland. The LHC is 27 kilometres in circumference, and as low as 175 metres below ground level at its deepest points.
The LHC is intended to collide opposing particle beams for the purpose of testing various predictions of high-energy physics, notably the existence of the hypothesized Higgs boson and of the large family of new particles predicted by supersymmetry. The beams will be composed of either protons at an energy of 7 TeV per particle, or lead nuclei at an energy of 574 TeV per nucleus.
On 10 September 2008, proton beams were successfully circulated in the main ring of the LHC for the first time. However, only 9 days later, operations were halted due to a serious fault between two superconducting bending magnets. Repairs and the installation of additional safety features have pushed back the operating date of the LHC, which is now planned to recommence operations in mid-November 2009.