It has to be Barcelona.
Barcelona won the champions league against Manchester united
Real Madrid with 9 (6 European Cup and 3 Champions League).
Nottingham Forest won the European Cup, the equivalent of the Champions League, 2 years running - in 1980 and 1981
Real Madrid has won the most Champions League titles (including European Cup).
Marseille were the first team to win the Champions League since it became a league format.
The team that won the UEFA Champions League in 1985 was Juventus.
The team that won the UEFA Champions League in 1970 was Feijenoord.
The team that won the UEFA Champions League in 1965 was Inter.
In 1999, Manchester United won the League title, FA cup and the European Cup (champions league).
Manchester United. Technically both times. They were the first English team to lift the old European Cup in 68, and then when it was changed to the Champions League, United won it again in 1999.