LNGS particle physics laboratory entrance. The Gran Sasso National Laboratory (LNGS), in Abruzzo, Italy, is one of four INFN (Italian national institute of nuclear physics) laboratories. The LNGS is located inside a mountain, and consists of three large experimental halls, each about 100 metres long, 20 metres wide and 18 metres. The mountain helps to shield the experiments from outside radiation, allowing the study by particle physicists and astrophysicists, of rare interactions involving neutrinos and other particles.