  The currently available empirical evidence on the star formation processes in
the extreme, high-pressure environments induced by galaxy encounters, mostly
based on high-resolution Hubble Space Telescope imaging observations, strongly
suggests that star CLUSTER formation is an important and perhaps even the
dominant mode of star formation in the starburst events associated with galaxy
interactions.
  The production of "super star clusters" (SSCs; luminous, compact star
clusters) seems to be a hallmark of intense star formation, particularly in
interacting and starburst galaxies. Their sizes, luminosities, and mass
estimates are entirely consistent with what is expected for young Milky
Way-type globular clusters (GCs). SSCs are important because of what they can
tell us about GC formation and evolution (e.g., initial characteristics and
early survival rates). They are also of prime importance as probes of the
formation and (chemical) evolution of their host galaxies, and of the initial
mass function in the extreme environments required for cluster formation.
Recent evidence lends support to the scenario that Milky Way-type GCs (although
more metal rich), which were once thought to be the oldest building blocks of
galaxies, are still forming today.
