The discovery of a binary black hole merger event in September 2015 has marked the birth of gravitational wave astronomy. So far three binary black hole merger events have been claimed, and the detection of merging binary neutron star and/or black hole-neutron star binary is imminent. Incoming data also starts to give us surprises, which challenge our previous understanding on the formation environment, distribution, physical properties of these compact object binary systems. In this talk I will first explain what are gravitational waves and then give a brief introduction of the history of development. After that I will review the status and recent progress of the field and discuss where we are heading in the next five/ten years.