Detection of gravitational wave signals from mergers of black holes and neutron stars is one the most important discoveries of this century. I shall briefly present the phenomenon of gravitational radiation as predicted by Einstein's general relativity. I shall describe gravitational wave detectors and
methods of analyzing gravitational wave data. I shall review the observations made during the two observational runs of advanced LIGO and Virgo detector projects. I shall present the physical and astrophysical significance of these observations. I shall summarize the most recent observations of gravitational wave signals made during the third observational run of LIGO and Virgo detectors that is currently underway.