The Large Hadron Collider (LHC) is the world's largest and highest-energy particle collider located at CERN near Geneva. Protons are accelerated and collided at energies of 7 TeV in the 27 km circular tunnel. Four detectors - ATLAS, CMS, ALICE, and LHCb - study the particles produced in the collisions to address fundamental questions in physics such as the discovery of the Higgs boson and exploration of dark matter and extra dimensions. The LHC began operations in 2008 but was halted that year due to an incident. It resumed collisions in 2009 and made its first major discovery of the Higgs boson in 2012.