Watch Inside CERN together — synced playback, live chat and reactions. Up to 12 people.
BBC Horizon follows the ups and downs of an outstanding story in particle physics. In June 2015, teams at CERN started running the large hadron collider at the highest energy ever. Rumours quickly emerged that they were on the brink of a huge discovery. An enigmatic bump in some data suggested a first glimpse of a brand new particle that could change our understanding of how the universe works.