On February 11, 2016, the Advanced LIGO team announced that they had directly detected gravitational waves from a pair of black holes merging. In June the Virgo team announced that they too had detected the waves.
In general relativity, gravitational waves cannot travel faster than the speed of light. They do not exist in the Newtonian theory of gravitation, in which physical interactions propagate at infinite speed. However, the detection of gravitational waves proves the last prediction of Einstein’s general theory of relativity.