The era of high precision Cosmology has shown our ignorance about the composition of the Universe. In this context, there has been a renewed interest on Alternative Theories of Gravity. Through the experience of a graviton measured by the LIGO collaboration, we shall understand the conceptual framework of those theories. They provide us with a theoretical construction where we can contrast the predictions of General Relativity and a possible scenario to describe the accelerated expansion of our Universe without assuming the existence of dark components. During the dawn of gravitational wave astronomy, gravitation is already promising to be one of the most fascinating fields of research of the XXI century.