Engineers are at tempting to circulate a beam of particles around the 27km-long underground tunnel which houses the Large Hadron Collider (LHC).
The £5bn machine on the Swiss-French border is designed to smash particles together with cataclysmic force, revealing signs of new physics. This will re-create conditions in the Universe moments after the Big Bang.
Scientists here will embark on their biggest experiment ever, the hunt for a particle which gave the universe its form. Its scientific name is the Higgs Boson, but because it is so fundamental in shaping the universe, others have called it the God particle.
It is a particle that is supposed to endow other fundamental particles with mass. Without it there would be no gravity, no universe as we know it – no "let there be light" moment.
No-one has seen it, but physicists have invoked it because it is the simplest explanation for how the universe evolved.