The CERN Neutrinos to Gran Sasso (CNGS) project is a physics project of the European Organization for Nuclear Research (CERN). The aim of the project is to analyse the hypothesis of neutrino oscillation by directing a beam of neutrinos from CERN's facilities to the detector of the OPERA experiment at the Gran Sasso National Laboratory (LNGS), located in the Gran Sasso mountain in Italy. The CNGS facility is housed at the Meyrin site of CERN, at the Franco–Swiss border near Geneva, Switzerland. It uses the Super Proton Synchrotron (SPS) accelerator as a source of high-energy protons.

The Oscillation Project with Emulsion-tRacking Apparatus (OPERA) is an instrument used in a scientific experiment for detecting tau neutrinos from muon neutrino oscillations. The experiment is a collaboration between CERN in Geneva, Switzerland, and the Laboratori Nazionali del Gran Sasso (LNGS) in Gran Sasso, Italy and uses the CERN Neutrinos to Gran Sasso (CNGS) neutrino beam.