Stellar clusters in the Gaia era
  Stellar clusters are important for astrophysics in many ways, for instance as
optimal tracers of the Galactic populations to which they belong or as one of
the best test bench for stellar evolutionary models. Gaia DR1, with TGAS, is
just skimming the wealth of exquisite information we are expecting from the
more advanced catalogues, but already offers good opportunities and indicates
the vast potentialities. Gaia results can be efficiently complemented by
ground-based data, in particular by large spectroscopic and photometric
surveys. Examples of some scientific results of the Gaia-ESO survey are
presented, as a teaser for what will be possible once advanced Gaia releases
and ground-based data will be combined.
