High Energy Neutrino Astronomy with the ANTARES Deep-Sea Telescope

The ANTARES detector is the most sensitive neutrino telescope on the northern hemisphere. It is installed in the Mediterranean Sea close to Toulon (France) at a depth of 2475m. Special aspects of a telescope in sea water are described. As an example for the first results, the determination of the atmospheric muon flux is discussed where a fair agreement with previous measurements is found. Further, the results of a search for high-energy events in excess of the atmospheric neutrino flux are reported and significant limits are set on the diffuse cosmic neutrino flux in the multi-TeV to PeV energy range.