High Energy Stereoscopic System (H.E.S.S.) is a system of imaging atmospheric Cherenkov telescopes (IACTs) for the investigation of cosmic gamma rays in the photon energy range of 0.03 to 100 TeV, located in the Khomas Region of Namibia and operating since 2002. The acronym was chosen in honour of Victor Hess, who discovered the extraterrestrial origin of cosmic rays.