The ANTARES detector: two decades of neutrino searches in the Mediterranean Sea

The ANTARES detector was the first neutrino telescope in seawater, operating successfully in the Mediterranean Sea in its full configuration from 2008 to 2022. All challenges related to the operation in the deep sea were accurately addressed by the Collaboration. Deployment and connection operations became smoother over time; data taking and constant re-calibration of the detector due to the variable environmental conditions were fully automated. Significant results on astroparticle physics, particle physics and multi-messenger astronomy have been obtained, despite the relative modest size of the detector, paving the way to a new generation of larger undersea detectors. In this contribution, the efforts by the ANTARES collaboration that made the possibility to operate neutrino telescopes in seawater a reality are summarized, together with the results obtained in this endeavor. The first part of this paper highlights some phases of the detector construction, while the second summarizes some scientific results not covered in other proceedings of this conference.