Most galaxies are believed to harbour a massive black hole at their center, and most galaxies are believed to merge with others during their life-time, perhaps many times. Such a merger will usually lead to a starburst ot the common center of the merged galaxy. Also, each time this happens, two black holes come close to each other, and may merge. We show that the torque exerted by the two black holes on the star distribution produces a belt-like configuration. Considering then the fraction of stars with appreciable mass loss, both newly formed massive stars, and old red giant stars, these many stellar winds are exposed to the radiation from the central engine and will form long outward pointed tails. We show that the sum of these tails may be optically thick, both geometrically and also to Thomson scattering, explaining the properties of the torus often inferred from IR and X-ray data in the centers of Active Galactic Nuclei. The torque on the stars leads to angular momentum loss to let the two black holes merge. The black hole merger then leads to ubiquitous emission of gravitational waves, which transport angular momentum. The dependence of this angular momentum loss on the spin parameters of the two black holes and their orbit is a challenge, critically relevant for gravitational wave experiments. This work was done with Christian Zier and Mihaela Chirvasa.