AGN Obscuration and the Unified Model
  Unification Models of Active Galactic Nuclei postulate that all the observed
differences between Type 1 and Type 2 objects are due to orientation effects
with respect to the line-of-sight to the observer. The key ingredient of these
models is the obscuring medium, historically envisaged as a toroidal structure
on a parsec scale. However, many results obtained in the last few years are
clearly showing the need for a more complex geometrical distribution of the
absorbing media. In this paper we review the various pieces of evidence for
obscuring media on different scales, from the vicinity of the black hole to the
host galaxy, in order to picture an updated unification scenario explaining the
complex observed phenomenology. We conclude by mentioning some of the open
issues.
