Answer
1. FC Kaiserslautern was the club that Ballack joined in 1997. This German football club, based in Kaiserslautern, Rhineland-Palatinate, currently plays in the 2. Bundesliga, the second tier of the German football league system. Ballack's move to Kaiserslautern marked a significant step in his career, as it provided him with a platform to showcase his skills and develop as a player.