Abstract. Gravitational waves are distortions in the fabric of space-time traveling at the speed of light. The first detections of gravitational waves from colliding black holes and neutron stars in 2015 and 2017 have only started the field of gravitational-wave astronomy. We can now 'hear' these cataclysmic events from distant galaxies.I will reflect upon what gravitational waves are, what has been measured to date,and how the complex (?) interferometers work that make these detections possible. The kilometer-scale laser interferometers, such as the two US-based LIGO detectors, combine elementsfrom different fields of physics and engineering, such as mechanics, optics, electronics, material science,feedback control, electronics, and simulations. I may briefly discuss other potential uses of precision laser interferometers, and I hope we can listen to the sound of the universe.