The LHC is designed to recreate the conditions that were present in the universe less than a billionth of a second after the big bang—and to do so again and again, up to 600 million times a second. It accomplishes this by accelerating protons, the atomic nuclei of hydrogen atoms, so close to the speed of light that they zip around the 17-mile ring 11,000 times a second, before colliding head-on with another beam of protons traveling in the opposite direction. Four giant experiments, ATLAS, CMS, LHCb and ALICE, "photograph" the resulting miniature "big bangs." I work with more than 2,000 other physicists from 37 countries on ATLAS, a detector that's been built from more component parts than a space shuttle and that fills a subterranean cavern bigger than the nave of St. Paul's Cathedral in London. The scale, ambition and unique international cooperation at CERN make it one of the greatest human endeavours of this or any century.