We present the simplest nuclear energy density functional (NEDF) to date, determined by only 4 significant phenomenological parameters, yet capable of fitting measured nuclear masses with better accuracy than the Bethe-Weizsäcker mass formula, while also describing density structures (charge radii, neutron skins etc.) and time-dependent phenomena (induced fission, giant resonances, low energy nuclear collisions, etc.). The 4 significant parameters are necessary to describe bulk nuclear properties (binding energies and charge radii); an additional 2 to 3 parameters have little influence on the bulk nuclear properties, but allow independent control of the density dependence of the symmetry energy, excitation energy of isovector excitations, and the Thomas-Reiche-Kuhn sum rule. This Hohenberg-Kohn-style of density functional theory (DFT) successfully realizes Weizsäcker's ideas and provides a computationally tractable model for a variety of static nuclear properties and dynamics, from finite nuclei to neutron stars, where it will also provide a new insight into the physics of the r-process, nucleosynthesis, neutron star crust structure, and neutron star mergers. This new NEDF clearly separates the bulk geometric properties -volume, surface, symmetry, and Coulomb energies which amount to ∼ 8 MeV per nucleon or up to ∼ 2000 MeV per nucleus for heavy nuclei -from finer details related to shell effects, pairing, isospin breaking, etc. which contribute at most a few MeV for the entire nucleus. Thus it provides a systematic framework for organizing various contributions to the NEDF. Measured and calculated physical observables -i.e. symmetry and saturation properties, the neutron matter equation of state, and the frequency of giant dipole resonances -lead directly to new terms, not considered in current NEDF parameterizations.