The Jiangmen Underground Neutrino Observatory (JUNO) is an underground 20 kton liquid scintillator detector being built in the south of China and expected to start data taking in 2020. JUNO has a physics programme focused on neutrino properties using electron anti-neutrinos emitted from two near-by nuclear power plants. Its primary aim is to determine the neutrino mass hierarchy from the ν¯e oscillation pattern. With an unprecedented relative energy resolution of 3% as target, JUNO will be able to do so with a statistical significance of 3-4 σ within six years of running. It will also measure other oscillation parameters to an accuracy better than 1%. An ambitious experimental programme is in place to develop and optimize the detector and t...