Large Hadron Collider (LHC) , the world’s most powerful Particle accelerator . The Large Hadron Collider (LHC) was constructed by the European Organization for Nuclear Research (CERN) in the same 27-km (17-mile) tunnel that housed its Large Electron-Positron Collider (LEP). The tunnel is circular and is located 50–175 metres (165–575 feet) belowground on the border between France and Switzerland . The LHC ran its first test operation on September 10, 2008. An electrical problem in a cooling system on September 18 resulted in a temperature increase of about 100 c (180 °F) in the magnets, which are meant to operate at temperatures near absolute zero (−273.15 °C, or −459.67 °F). Early estimates that the LHC would be quickly fixed soon turned out to be overly optimistic . It restarted on November 20, 2009. Shortly thereafter, on November 30, it supplanted the Fermi National Accelerator Laboratory ’s Tevatron as the most powerful particle accelerator when it boosted proto