Chelsea Football Club are an English professional football club based in west London. Founded in 1905, they play in the Premier League and have spent most of their history in the top tier in English football.
In 2005, Chelsea's centenary year, the club became Premiership champions in a record-breaking season, League Cup winners with a 3–2 win over Liverpool and reached the Champions League semi-finals. The following year, they were again League Champions, equalling their own Premiership record of 29 wins set the previous season. They also became the fifth team to win back-to-back championships since the Second World War and the first London club to do so since Arsenal in 1933–34.
Chelsea's home is the Stamford Bridge football stadium in Fulham, west London, where they have played since their foundation. Chelsea are one of the best-supported clubs in the United Kingdom, with an estimated four million fans.