A proposed experiment designed to answer many of the questions about neutrinos that are presently unresolved. In particular, DUNE will search for CP violation (see CP invariance) in neutrinos using a 1300 km-long beam between Fermilab, near Chicago, and the Sanford Underground Research Facility, South Dakota. Other objectives of DUNE are to determine the ordering of neutrino masses and to investigate whether there are other types of neutrino in addition to the three types presently known. It is hoped that DUNE will be operational by 2030.