The site of r-process nucleosynthesis, which forges some of the heaviest elements in the periodic table, has been a long-standing mystery in astrophysics. Electromagnetic follow-up observations of the gravitational wave-detected binary neutron star merger GW170817 suggested that material ejected during the merger underwent a robust r-process, burning elements such as Au, Pt, and Eu. However, uncertainties in the interpretation of the electromagnetic signal, as well as doubts about mergers’ ability to synthesize r-process elements in all the environments in which they are observed, raise the question of whether mergers are unique sites of r-process production. I will discuss ongoing work into the uncertainties surrounding the interpretation of the electromagnetic signatures from neutron star mergers, consider the possibility that rare core-collapse supernovae might be important alternative sources of r-process material, and outline how a combination of modeling and observation can help resolve the mysteries of astrophysical nucleosynthesis.