The Large High Altitude Air Shower Observatory (LHAASO) has made a breakthrough in exploring the extreme universe. For the first time, the LHAASO collaboration has detected ultra-high-energy (UHE) gamma rays—with energies exceeding 100 trillion electron-volts (TeV)—from a gamma-ray binary system, LS I +61° 303. The discovery challenges existing theories of particle acceleration in extreme astrophysical environments.