1. FC Union Berlin, officially 1. Fußballclub Union Berlin e. V., is a football club based in Berlin-Köpenick. Its founding story is complicated. In 1906, in a sandpit behind the school in what is now Plönzeile, ball boys and friends from the local club Excelsior founded the football club Olympia.\n\nThat club quickly dissolved, but football enthusiasts from the same environment soon formed a new side inspired by nearby Lichtenberger SC Frisch Auf.
Excelsior split into Preußen and Vorwärts, but neither breakaway lasted for long.