On September 14th, 2015, the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) observed gravitational waves from a binary black hole coalescence. I will discuss the context and implications of this discovery. In particular, I will give an introduction to gravitational waves and prominent astrophysical sources, describe how LIGO is able to detect gravitational waves, and explain how to find gravitational wave signals in LIGO data.

I will then describe the (astro)physics we have gleaned from this first discovery, from binary black hole coalescence rates to tests of general relativity. I will end by looking forward to the many exciting future prospects for gravitational wave observations.