We describe Einstein's theoretical prediction from his general relativity, the first gravitational wave detectors from the 1960s, astronomical confirmation of the existence of gravitational waves by monitoring the PSR B1913+16 binary pulsar, the technical parameters of today's highly sensitive Advanced LIGO and Virgo interferometers, details of historical GW150914 signal, for which the Nobel Prize was awarded in 2017, other observed gravitaional waves, as well as the promising future of the new field of gravitational astronomy, enabling us to be observe the universe through "many observation windows".