The Laser Interferometer Gravitational-Wave Observatory (LIGO) simultaneously observed a transient gravitational-wave signal, produced by the merger of two Black Holes.

100 years after Albert Einstein's prediction.

LIGO scientists estimated the black holes were about 29 and 36 times the mass of the sun, and the event took place 1.3 billion years ago.

Gravitational Waves Detected 100 Years After Einstein's Prediction

This entertaining video gives you a full explanation of Gravitational Waves.

Gravitational waves provide a completely new way at looking at the Universe. The ability to detect them has the potential to revolutionise astronomy. This discovery is the first detection of a black hole binary system and the first observation of black holes merging. Apart from testing (Albert Einstein's theory of) General Relativity, we could hope to see black holes through the history of the Universe. We may even see relics of the very early Universe during the Big Bang at some of the most extreme energies possible.

- Prof Stephen Hawking, who is an expert on black holes.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102
http://9gag.com/tv/p/amjdpy/gravitational-waves-explained
http://www.bbc.com/news/science-environment-35524440