CRC 1245 “Nuclei: From Fundamental Interactions to Structure and Stars” investigates the strong and electroweak interaction physics from nuclei to stars. The physics of nucleonic matter ranges from universal properties at low densities to the densest matter we know to exist in neutron stars. Chiral effective field theory provides a link between nuclear structure and matter in stars with the underlying theory of the strong interaction. The pioneering work in this CRC, accessing the medium-mass region of nuclei, provides the basis for the ultimate goal of a consistent description of nuclear structure across the nuclear chart into the heavy-mass region of nuclei and for matter in stars. Additionally, strong and electroweak processes are key to understanding the chemical contribution from supernovae and neutron star mergers to the Universe, and will provide systematic uncertainties for nuclear matrix elements required to test fundamental symmetries. The reach of CRC 1245 thus extends well beyond nuclear physics with a demonstrated impact on neutrino physics, astroparticle physics, and astrophysics.