Largest particle accelerator
Large Hadron Collider
Switzerland (Geneva )

The Large Hadron Collider is the largest and most complex machine ever built. It consists of a 27 km (approx. 17 miles) long circular tunnel under the ground on the Franco-Swiss border near Geneva, Switzerland. Its aim is to smash together two opposing beams of protons at extremely high energies in order to witness the results of their collisions. The most famous goal of this experiment is to find the theorised Higgs boson, which so far has eluded discovery.