  We experimentally show that dipolar interaction can stabilize otherwise
unstable many-body systems like an attractive Bose gas. In a one dimensional
lattice the repulsive dipolar on-site interaction balances negative scattering
lengths up to -17 Bohr radii and stabilizes the chromium Bose-Einstein
condensate. For reduced lattice depths, the dipolar stabilization turns into
destabilization. We probe the full cross-over between the two regimes and our
results are in excellent agreement with theoretical calculations, which reveal
significant dipolar inter-site interactions.
