  We have computed the next-to-next-to-leading-order (NNLO) contributions to
the evolution of unpolarized parton distributions in perturbative QCD. In this
talk, we briefly recall why this huge computation was necessary and outline how
it was performed. We then illustrate the structure of the results and discuss
their end-point limits which include the three-loop cusp anomalous dimensions
of the Wilson lines. Finally the numerical impact of the new contributions is
illustrated.
