Gravitational waves are distortions in the fabric of space and time that are a prediction of general relativity made shortly after the formulation of the theory. One-hundred years after their prediction, the LIGO and Virgo detectors observed the gravitational waves from a collision of two black holes. In the past decade, the detectors have measured gravitational waves from hundreds of other pairs of black holes. In this talk, I will review the status of these gravitational-wave detections and describe their implications for understanding gravitational physics. As an example, I will discuss plans for future gravitational-wave detectors and describe their capacities for observing black-hole mergers.