Beneath the Franco-Swiss border, engineers at CERN sent the first beam of protons all the way around the 27-kilometer ring of the Large Hadron Collider, a machine built to recreate conditions microseconds after the Big Bang. The successful test marked the culmination of nearly two decades of design and construction and set the stage for the eventual discovery of the Higgs boson in 2012.
The Large Hadron Collider had cost roughly $9 billion and involved thousands of scientists from over a hundred countries. When the first beam completed its full circuit at 10:28 a.m., control room engineers erupted in applause; the moment was broadcast live around the world, with some media outlets breathlessly speculating the machine might create a black hole that could swallow the planet.
Just nine days later, on September 19, a faulty electrical connection between two magnets caused a helium leak that damaged over 50 magnets and forced a 14-month shutdown for repairs. The collider didn't reach full operational collisions until November 2009. But the September 10 startup remained a landmark moment—proof that humanity could build and operate the most complex scientific instrument ever constructed, one that would go on to confirm the existence of the Higgs boson and reshape particle physics.