Explore the CERN accelerator complex, filmed during the exceptional #CERNOpenDays visits. Each Sunday evening, we will release a new video. Watch the fourth episode, featuring the places where we collide particles in the LHC. Did you know that the beams inside the LHC are made to collide at four locations around the accelerator ring, corresponding to the positions of four particle detectors – ATLAS Experiment at CERN, CMS Experiment at CERN, ALICE experiment and LHCb Experiment at CERN? Find out