  Star formation may take place in a variety of locations in interacting
systems: in the dense core of mergers, in the shock regions at the interface of
the colliding galaxies and even within the tidal debris expelled into the
intergalactic medium. Along tidal tails, objects may be formed with masses
ranging from those of super-star clusters to dwarf galaxies: the so-called
Tidal Dwarf Galaxies (TDGs). Based on a set of multi-wavelength observations
and extensive numerical simulations, we show how TDGs may simultaneously be
used as laboratories to study the process of star-formation (SFE, IMF) in a
specific environment and as probes of various cosmological properties, such as
the distribution of dark matter and satellites around galaxies.
