The GRAPES-3 experiment in Ooty, India, operated by the Tata Institute of Fundamental Research has discovered a new feature in the cosmic-ray proton spectrum at about 166 tera-electron-volt (TeV) energy while measuring the spectrum spanning from 50 TeV to a little over 1 peta-electron-volt (PeV). The observed feature suggests a potential re-evaluation of our understanding of cosmic-ray sources, acceleration mechanisms, and their propagation within our galaxy.