Watching the first kilonova, an explosion discovered from the gravitational waves from merging neutron stars // In August 2017, the LIGO and Virgo gravitational wave observatories detected their first neutron star collision, which were predicted to produce optical counterparts that we could observe with traditional telescopes. We quickly began searching for the optical counterpart of the gravitational-wave signal using Las Cumbres Observatory (LCO), a unique followup facility ideally suited for observing fast astronomical transients. LCO consists of 20 telescopes at 6 sites around the world, working as one robotic, dynamically scheduled global network. Using LCO, we were able detect the ensuing explosion produced by the neutron star merger, a "kilonova", which rose and faded in less than a week. I will present our observations from LCO and other spectroscopic facilities of the kilonova and discuss their implications for the amount of heavy r-process elements that were produced in this new type of cosmic explosion.