  For the celebrations of the 100 years of the observations undertaken by
Eddington at the island of Principe and collaborators at Sobral during a total
solar eclipse in May 29, 1919, which have confirmed Einstein's theory of
general relativity through the deflection of the incoming light from distant
stars due to the spacetime curvature caused by the Sun, we highlight the main
aspects of the theory, its tests and applications, focusing on some of its
outstanding consequences. These are black holes, the object par excellence of
general relativity, and gravitational waves, the gravitational probe for the
distant Universe. We also point out some open issues.
