Between October 1999 and October 2000 an undistinguished high-galactic latitude patch of sky, the Hubble Deep Field South (HDF-S), was observed with the VLT for more than 100 hours under the best seeing conditions. Using the near-infrared (NIR) imaging mode of the Infrared Spectrometer and Array Camera (ISAAC, Moorwood 1997), we obtained ultradeep images in the Js (1.24 μm), H (1.65 μm) and Ks (2.16 μm) bands. The combined power of an 8-metre-class telescope and the highquality wide-field imaging capabilities of ISAAC resulted in the deepest groundbased NIR observations to date, and the deepest Ks-band in any field. The first results are spectacular, demonstrating the necessity of this deep NIR imaging, and having direct consequences for our understanding of galaxy formation.