The UEFA Champions League, or simply known as the UCL is a football competition organized by UEFA, between some of the top club teams in Europe. The top team in the league comes out UEFA champions league every year. 32 teams will play the game and determines the best football club. At first, it was started by France, not the European Football Federation. It was played only as a home and away tournament, but a group stage was added from the 1991-92 season. The teams are selected because of good performances in their respective domestic leagues. The teams used to have to win their countries' league, but more than one team can play in the competition depending on how good their league is. For example: the Spanish League can get 4 Spanish clubs in the competition compared to the Kazakhstan League which can only get one team in the competition.
Real Madrid won the Champions League the first five times it was held, still a record. They have also won the Champions League/European Cup 15 times, which is also a record.