© EHT Collaboration, Fermi-LAT Collaboration, H.E.S.S. Collaboration, MAGIC Collaboration, VERITAS Collaboration, EAVN Collaboration© EHT Collaboration, Fermi-LAT Collaboration, H.E.S.S. "We were lucky to detect a gamma-ray flare from M87 during this Event Horizon Telescope's multi-wavelength campaign. This marks the first gamma-ray flaring event observed in this source in over a decade, allowing us to precisely constrain the size of the region responsible for the observed gamma-ray emission. It is possible that ultra-high-energy particles underwent additional acceleration within the same emission region observed in quiet states, or that new acceleration occurred in a different emission region."