Gravitational waves from black hole mergers: did LIGO detect dark matter?

One of the most fascinating predictions of Einstein's theory of gravity is the existence of black holes: objects that are so dense that not even light can escape their powerful gravitational attraction. The Laser Interferometer Gravitational-Wave Observatory (LIGO) has recently discovered the presence of a population of black holes that could constitute the dark matter in the universe. In this talk we will discuss the implications of these results, as well as the observations of the super-massive black hole at the center of the Milky Way by the Event Horizon telescope.