"The UEFA Champions League, known simply as the Champions League, and originally known as the European Champion Clubs' Cup or European Cup, is an annual continental club football competition organised by the Union of European Football Associations (UEFA) since 1955 for the top football clubs in Europe. It is one of the most prestigious tournaments in the world and the most prestigious club competition in European football. The final of the 2013 tournament was the most-watched UEFA Champions League final to date, as well as the most watched annual sporting event worldwide in 2013 to date, drawing 360 million television viewers.
Prior to 1992, the tournament was officially called the "European Champion Clubs' Cup", but was usually referred to simply as the "European Cup". The competition was initially a straight knockout competition open only to the champion club of each country. During the 1990s, the tournament began to be expanded, incorporating a round-robin group phase and more teams. Europe's strongest national leagues now provide up to four teams for the competition and will provide up to five teams from the 2015–16 competition onwards. The UEFA Champions League should not be confused with the UEFA Europa League, formerly known as the UEFA Cup.
Contributions by Dale Arnett, 18.104.22.168, and Hammersfan."