  Core-Collapse supernovae arise from stars greater than 8 $\msun$. These stars
lose a considerable amount of mass during their lifetime, which accumulates
around the star forming wind-blown bubbles. Upon the death of the star in a
spectacular explosion, the resulting SN shock wave will interact with this
modified medium. We study the evolution of the shock wave, and investigate the
properties of this interaction. We concentrate on the evolution of the SN shock
wave in the medium around a 35 solar mass star. We discuss the hydrodynamics of
the resulting interaction, the formation and growth of instabilities, and
deviations from sphericity.
