  Globular clusters (GCs) constitute a system which is evolving because of
various interactions with the galactic environment. Evolution may be the
explanation of many observed features of Globular Cluster Systems (GCSs); the
different radial distribution of the GCS and the stellar component of early
type galaxies is explained by dynamical friction and tidal effects, this latter
acting both on the large scale (that of the bulge-halo stars) and on the small
scale (that of the nucleus, often containing a central massive black hole).
Merging of quickly orbitally decayed massive GCs leads to formation of a Super
Star Cluster (SSC) which enriches the galactic nucleus and is a reservoire of
mass-energy for a centrally located black hole
