The Deep Underground Neutrino Experiment, or DUNE, is a large U.S.-hosted international physics project linking a near detector at Fermilab in Illinois with a far detector deep underground in South Dakota. It will send a beam of neutrinos through the Earth to study neutrino oscillations, possible CP violation, the ordering of neutrino masses, supernova neutrinos, and proton decay. Emerging from the earlier LBNE effort and elevated as a top priority in 2014, DUNE has grown to include collaborators from more than 30 countries. Its immense scale includes major excavation, advanced liquid-argon detector technology, and a multibillion-dollar phased construction program.