By accomplishing one more step towards the unification of all the fundamental forces, S. Glashow, S. Weinberg et A. Salam were walking in Newton, Maxwell, Einstein's steps, and many others who were tending to a theory which would apply anywhere, which is supported by the observation that our Universe was born from a unique, compact and causal in a homogeneous space.
From there, particle physics research has never stopped verifying the predictions of this new theory. Essentially, the largest programs (SPS, Tevatron, LEP, HERA, LHC ...) targeted the observation of new phenomena: neutral currents, W & Z bosons and the Higgs, Englert and Brout boson.
Today, these phenomena have almost all become standard. A Higgs boson has been observed by two LHC experiments, including ATLAS. Its complete study remains the main programme of the LHC.
Despite its incredible discovery power, the LHC could not be a powerful enough machine to study in detail the decay modes of the discovered Higgs boson. The ILC (International Linear Collider) project will aim at overcoming this by means of very high luminosity electron-positron collisions with centre of mass energies between 90 and 1000 GeV.