On August 17th, the first gravitational-wave signal from the merging of two neutron stars was discovered. Two seconds later, a burst of gamma-rays was detected, making this the first event seen in both gravitational waves and electromagnetic radiation. A few hours later, the associated "kilonova" was discovered by optical telescopes, making this also the first gravitational-wave source to be localized to a specific galaxy, and at 40 Mpc, also the closest gravitational wave event ever detected. In an unprecedented follow-up campaign, the event was observed by over 70 telescopes in the X-ray, UV, optical, infrared and radio bands, making this the best observed transient in history. The optical and infrared emissions are unlike anything ever seen before, but their striking match to theoretical predictions confirms that merging neutron stars are likely the dominant source of heavy r-process elements in the Universe. However, some aspects of the rich emission properties confront theory and present a challenge to models. I will discuss this discovery, how our program at Las Cumbres Observatory was one of the first to detect the kilonova, how our unique global network of telescopes obtained the best optical coverage of this event, and how the data collected in the over 80 papers published on day one has implications from nuclear physics to cosmology.