  We present some features of Kerr black hole horizons that are replicated on
orbits accessible to outside observers. We use the concepts of horizon
confinement and replicas to show that outside the outer horizon there exist
photon orbits whose frequencies contain information about the inner horizon and
that can, in principle, be detected through the emission spectra of black
holes. It is shown that such photon orbits exist close to the rotation axis of
the Kerr geometry. We argue that these results could be used to recognize and
further investigate black holes and their horizons
