KM3NET: A Deep-Sea Neutrino Telescope in the Mediterranean Sea

KM3NET (KM3 NEutrino Telescope) is a future deep-sea research infrastructure located in the Mediterranean Sea. It comprises a km3-scale neutrino telescope and facilities for marine research. The members of the three ongoing neutrino projects in the Mediteranean (Antares, Nemo, Nestor) are participating to a design study, partially funded by the EU, to optimise the sensitivity of the design for the detection of high-energy neutrinos. The status of the project, technical options and expected sensitivity to a variety of astrophysical sources are presented.