The High Energy Stereoscopic System (H.E.S.S.) is a new instrument to explore the southern sky at TeV energies. Since December 2003, the four H.E.S.S. imaging Cherenkov telescopes are operational in Namibia. Compared to the previous generation, H.E.S.S. is an order of magnitude more sensitive. First data from H.E.S.S. demonstrate the power of the instrument and include the first resolved image of a supernova shell at TeV energies and the study of very high energy gamma-ray emission from the Galactic Centre.