1. Fußballclub Union Berlin e. V., commonly known as 1. FC Union Berlin or simply Union Berlin, is a professional German association football club based in the locality of Kopenick of the borough of Treptow-Kopenick of Berlin. The club emerged under the current name in 1966 but its origins can be traced back to 1906, when its predecessor FC Olympia Oberschoneweide was founded. From 2009 until 2019, they competed in the 2. Bundesliga, the second tier of German football. In 2019, after defeating VfB Stuttgart in the relegation play-offs, Union won promotion to the Bundesliga top flight for the first time in the club's history, for the 2019–20 season.