  The recent detection by Advanced LIGO of gravitational waves (GW) from the
merging of a binary black hole system sets new limits on the merging rates of
massive primordial black holes (PBH) that could be a significant fraction or
even the totality of the dark matter in the Universe. aLIGO opens the way to
the determination of the distribution and clustering of such massive PBH. If
PBH clusters have a similar density to the one observed in ultra-faint dwarf
galaxies, we find merging rates comparable to aLIGO expectations. Massive PBH
dark matter predicts the existence of thousands of those dwarf galaxies where
star formation is unlikely because of gas accretion onto PBH, which would
possibly provide a solution to the missing satellite and too-big-to-fail
problems. Finally, we study the possibility of using aLIGO and future GW
antennas to measure the abundance and mass distribution of PBH in the range [5
- 200] Msun to 10\% accuracy.
