Conceptual illustration of the Higgs particle (orange, top and bottom) being produced by colliding two protons. The protons are each composed of three quarks (green and blue) held together by the strong nuclear force carried by gluons (white squiggly lines). The Higgs boson, long expected to exist according to theory, was finally revealed in proton-proton collisions conducted using the Large Hadron Collider (LHC) at CERN in Switzerland, 2012.