Einstein is Newton with Space Curved

The two defining features of the Einsteinian gravity are that it is self-interactive and it links universally to all particles, including zero-mass particles. In the process of obtaining the Schwarzschild solution for gravitational field of a mass point, we demonstrate how these features are incorporated? We also show, unlike the Newtonian gravity, why gravitational potential in the Schwarzschild solution can have its zero only at infinity and nowhere else, i.e. it is determined absolutely. Further we consider particle orbits to expose certain insightful and subtle points of concept and principle.