The exciting discoveries of TeV gamma-ray sources by the High Energy Stereoscopic System (HESS) of imaging atmospheric Cherenkov telescopes elevated the status of the field from "an Astronomy with several sources" to a truly observational discipline with a great potential for spectrometric, morphological and temporal studies of objects representing several nonthermal galactic and extragalactic source populations. I will highlight the recent observations of HESS, and discuss the astrophysical and cosmological implications of these results.