The gravitational waves were detected directly for the first time on September 14 at 18:51 (Korean Standard Time) by twin LIGO detectors located at Livingston, Louisiana and Hanford, Washington nearly simultaneously. This signal was initially noticed by the detection software within 3 minutes of the arrival, but final confirmation was made only after long and careful investigation of the noise characteristics, shape of the signal and possible influence of the environment.  We finally concluded that the detected waves were produced during the last fraction of second of the inspiral and merger of a binary system composed of two black holes of about 39 and 26 Msun each, located at about 1.3 billion light years. During this process, huge amount of energy corresponding to approximately 3 Msun in the form of gravitational waves has been radiated away, leaving a single black hole of about 62 solar mass behind. In this talk, I will briefly describe the nature of the nature of gravitational waves, the principle of the LIGO detectors and their sensitivities, and how actual detection was made. Then I will close my talk by commenting on the prospect of the gravitational wave astronomy brought by this detection.