The Liquid Argon Time Projection Chamber (LAr TPC) is a detection technique very well suited for the investigation of rare signals, including neutrino interactions. The ICARUS T600 is the largest LAr TPC ever built. It has recorded events both, from the CERN to Gran Sasso (CNGS) muon neutrino beam and cosmic rays interactions. Several important results have been achieved thanks to the three-dimensional event imaging and very good detector resolutions both, calorimetric and spatial. Two of them, namely the observation of a free electron lifetime exceeding 15 ms, and the search of LSND related anomalies in the νe appearance from the νμ CNGS beam will be shortly summarized.