General relativity (GR) is the geometrical theory of gravitation published by Albert Einstein in 1915.
It unifies special relativity and Sir Isaac Newton's law of universal gravitation with the insight that gravitation is not due to a force but rather is a manifestation of curved space and time, with this curvature being produced by the mass-energy and momentum content of the spacetime.
General relativity is distinguished from other metric theories of gravitation by its use of the Einstein field equations to relate spacetime content and spacetime curvature.
General relativity is currently the most successful gravitational theory, being almost universally accepted and well confirmed by observations.
The first success of general relativity was in explaining the anomalous perihelion precession of Mercury.
Then in 1919, Sir Arthur Eddington announced that observations of stars near the eclipsed Sun confirmed general relativity's prediction that massive objects bend light.
Since then, many other observations and experiments have confirmed many of the predictions of general relativity, including gravitational time dilation, the gravitational redshift of light, signal delay, and gravitational radiation.
In addition, numerous observations are interpreted as confirming the weirdest prediction of general relativity, the existence of black holes.