For a few years, a new physics has been developing: this is non-linear physics, which leads to turbulence and chaos. Non-linear theories in physics are present in many fields, and especially in fluid dynamics, with the hydrodynamics instabilities. All these physical instabilities have their basis in a mathematical theory: the non-linear system theory, or dynamical differentiable systems theory. This non-linear physics is fascinating, and the chaotic appearance of these strange phenomena leads to a conceptual unification, with the famous notions of bifurcations, strange attractors, Lyapunov exponents and so on.Here we will focalize our interest on an example of strange attractor, the Henon attractor: we will present its fractal structure, and some interesting features related to its strange attractor status.