Large Hadron Collider:
Large Hadron Collider is the world’s most powerful particle accelerator. It 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 meters (165–575 feet) below ground, on the border between France and Switzerland.