Key ring "LHC launch key"

The Large Hadron Collider (LHC) is the world’s largest and most powerful particle accelerator. It first started up on 10 September 2008 and is the latest addition to CERN’s accelerator complex. The LHC consists of a 27 km ring of superconducting magnets with a number of accelerating structures that boost the energy of the particles along the way.

As you may have guessed, it takes more than just a simple key to start it!

The accelerators are controlled by operators 24 hours a day from the CERN Control Centre.

More about particle accelerators.
More about the CERN accelerator complex.