CERN's Large Hadron Collider came back online last week after a three-year break for maintenance and upgrades; yesterday, the collaboration announced that two proton beams had been accelerated to a record energy of 6.8 tera-electron volts (TeV) per beam.The LHC is a nearly 17-mile-circumference particle collider in Switzerland. The circular collider has been instrumental in physics breakthroughs, including the discovery of the Higgs boson in 2012. Twice it has been shut down for prolonged periods so scientists could make improvements to its efficiency.