The construction of ANTARES, the first undersea neutrino telescope

With nearly 900 large-area photomultipliers installed on 12 detection lines at 2500 m depth in the Mediterranean, ANTARES is the first undersea neutrino telescope and the largest volume detector currently operated in the northern hemisphere. The construction of the apparatus was completed in May 2008 with the connection of the two last detection lines. The data sample collected so far contains more than 5×107 triggered events, out of which more than 400 candidate neutrino events have been already identified. In this paper we illustrate the apparatus design, summarize the construction operations, report on the current status of the experiment and discuss its discovery potentials.