Misfolded ?-synuclein amyloid fibrils are the principal components of Lewy bodies and neurites, hallmarks of Parkinson's disease (PD). In this paper, we present a high-resolution structure of an ?-synuclein fibril, in a form that induces robust pathology in primary neuronal culture, determined by solid-state NMR spectroscopy and validated by EM and X-ray fiber diffraction. Over 200 unique long-range distance restraints define a consensus structure with common amyloid features including parallel, in-register ?-sheets and hydrophobic-core residues, and with substantial complexity arising from diverse structural features including an intermolecular salt bridge, a glutamine ladder, close backbone interactions involving small residues, and several steric zippers stabilizing a new orthogonal Greek-key topology. These characteristics contribute to the robust propagation of this fibril form, as supported by the structural similarity of early-onset-PD mutants. Finally, the structure provides a framework for understanding the interactions of ?-synuclein with other proteins and small molecules, to aid in PD diagnosis and treatment.