  The recent detections of gravitational waves from binary systems of black
holes are in remarkable agreement with the predictions of General Relativity.
In this pedagogical mini-review, I will go through the physics of the different
phases of the evolution of black hole binary systems, providing a qualitative
physical interpretation of each one of them. I will also briefly describe how
these phases would be modified if gravitation were described by a theory
extending or deforming General Relativity, or if the binary components turned
out to be more exotic compact objects than black holes.
