In terms of scale, it is the biggest scientific experiment ever undertaken.
Thousands of scientists at the European Organisation for Nuclear Research, or CERN, have been working to perfect their particle collider since its inception in 1994.
The huge circular tunnel contains more than 1,000 cylindrical magnets arranged end-to-end.
The researchers’ purpose is to steer the beam – made up of particles called protons – around the27-kilometre circuit.
Two channels of protons, racing at a speed of 11,000 laps of the tunnel per second, will eventually be made to collide at close to the speed of light.
Four huge detectors will monitor the collisions for interesting events.
Scientists are hoping that new sub-atomic particles will emerge, revealing fundamental insights into the nature of the cosmos.
They are searching for the Higgs-Boson particle, which they say explains the origin of mass in the universe, and hope to better understand “dark matter” and the existence of other dimensions.