The Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung m. b. H. (English: Berlin Electron Storage Ring Society for Synchrotron Radiation), abbreviated BESSY, is a research establishment in the Adlershof district of Berlin. Founded on 5 March 1979, it currently operates one of Germany's 3rd generation synchrotron radiation facilities, BESSY II.