The KM3NeT Collaboration was formed to build, install and operate the first phase of the KM3NeT Research Infrastructure in the Mediterranean Sea which houses a network of neutrino detectors and ports for Earth and Sea science research. KM3NeT-phase1 is an essential step toward a second phase which foresees the construction of ARCA for high energy neutrino astronomy and ORCA for the determination of the Neutrino Mass Hierarchy. The collaboration includes about 250 people worldwide.