Answer
Karen retired while playing for Chelsea, a professional football club based in Fulham, London, England. Founded in 1905, Chelsea is renowned for its rich history, passionate fanbase, and numerous achievements. The club has won several major trophies, including the Premier League, FA Cup, UEFA Champions League, and UEFA Europa League. With a state-of-the-art stadium, Stamford Bridge, Chelsea is a force to be reckoned with in English and European football.