Galaxies are gigantic complex structures and understanding how they are formed and evolve is a difficult matter. But one thing we do know, they feed from each other. Under the current paradigm of galaxy evolution, big galaxies have grown by assimilating smaller galaxies. This kind of events usually produce the most astonishingly beautiful images that can be taken with telescopes. But what is really happening when two galaxies collide? Is there really any violence involved at all? Should we be worried that our galaxy will be eaten as well? In this talk we will answer all these questions and learn about the latest developments in our understanding of galaxies.