The Large Hadron Collider at CERN is running again now for 2023, which means it’s no longer possible to go underground (due to the synchrotron radiation, it’s not good to be next to the LHC while it’s running). But before we turned back on again for this year, I went underground together with my colleague Dylan Van Arneman from Nikhef and we recorded a live tour of the ATLAS detector cavern. Join us on this fascinating journey through one of the largest and most complex scientific experiments in the world!