The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector that will study the reactor antineutrinos emitted by two nuclear power plants in the southeast of China at a baseline of about 53 km. With an unprecedented energy resolution of 3% at 1 MeV, JUNO will be able to determine the neutrino mass ordering at 3-4 sigma significance within six years of running. JUNO will also be able to measure three oscillation parameters to an accuracy better than 1%, and to study neutrinos from various terrestrial and extra-terrestrial sources. The experiment is currently under construction, and detector completion is expected by 2021. JUNO's physics prospects, design and status are discussed here.