One of the significant complexities of aromatic compounds in the context of nuclear magnetic resonance spectroscopy is that an external magnetic field causes the electrons of an aromatic π system to circulate and generate an induced field that opposes the applied field inside the ring and adds to it outside the ring. The hydrogens on an aromatic ring are outside the ring, of course, so on an NMR spectrograph, these protons are shifted downfield due to the support of the applied field by the induced field.