Bayer 04 Leverkusen Fußball GmbH, also known as Bayer 04 Leverkusen , Bayer Leverkusen, Leverkusen or simply Bayer, is a German football club based in Leverkusen, North Rhine-Westphalia. The club plays in the Bundesliga, the top tier of the German football league system, and host matches at the BayArena. The club was founded in 1904 by employees of the German pharmaceutical company Bayer, whose headquarters are in Leverkusen and from which the club draws its name. It was formerly the best-known department of TSV Bayer 04 Leverkusen, a sports club whose members also participate in athletics, gymnastics, basketball and other sports including the RTHC Bayer Leverkusen (rowing, tennis and hockey). In 1999 the football department was separated from the sports club and is now a separate entity formally called Bayer 04 Leverkusen GmbH. Bayer Leverkusen have won one DFB-Pokal and one UEFA Cup. Their local rivals are 1. FC Köln.

BayArena

RasenBallsport Leipzig e.V., commonly known as RB Leipzig, is a German association football club based in Leipzig, Saxony. The club was founded in 2009 by initiative of the company Red Bull GmbH—which purchased the playing rights of a fifth-tier side, SSV Markranstädt, with the intent of advancing the new club to the top-flight Bundesliga within eight years. Men's professional football is run by the spin-off organization RasenballSport Leipzig GmbH. RB Leipzig plays its home matches at the Red Bull Arena. In its inaugural season in 2009–10, RB Leipzig dominated the NOFV-Oberliga Süd (V) and was promoted as champions to the Regionalliga Nord (IV). RB Leipzig won the 2012–13 Regionalliga Nordost season without a single defeat and was promoted to the 3. Liga (III), then finished the 2013–14 3. Liga season as runners-up and was promoted to the 2. Bundesliga (II) as the first team since the introduction of the 3. Liga to win promotion after only one season. On 8 May 2016, RB Leipzig ensured promotion to the Bundesliga for the 2016–17 season with a 2–0 win over Karlsruher SC. One year later, RB Leipzig captured a place in the 2017–18 UEFA Champions League by finishing as runners-up of the Bundesliga.