  Discovery of GRB clusters allows us to determine coordinates and
characteristics of their sources. The objects radiating GRBs are reliably
identified with black hole binaries, including the Galactic binaries. One of
the unusual GRB properties, which are determined by black hole, is revealed in
that the measured arrival direction of GRB does not coincide with the real
location of its source. Just this fact allows us to find the objects radiating
GRBs. On the basis of the general relativity theory's effects, observed in the
GRB clusters, the technique of the black hole masses measurement is developed.
The calculated black hole masses for the majority of known Galactic BH binaries
are presented. It is briefly shown how the incorrect interpretations of
observational facts result in an erroneous idea of the GRB cosmological origin.
In fact, two problems are solved in the paper: the GRB origin and the reality
of BH existence.
