Gravitational-wave observatories are currently revolutionizing astrophysics and astronomy. Detections of neutron star mergers trigger follow-up campaigns of unprecedented scope by astronomers and astroparticle physicists worldwide. What do these new messengers—-gravity, light, and particles—-tell us about the Universe? One exciting fundamental question to ask in this context relates to the origin of the heavy elements in our periodic table: How does the Universe create the so-called rapid neutron-capture elements, whose cosmic origin has been a mystery for more than six decades? In this talk, I will attempt to provide an overview of some exciting recent developments at the interface of strong gravity, high-energy astrophysics, and nuclear physics.