UEFA Champions League is the most popular football club competition in the world, with more than 300 millions television audience it`s most watched sport event. The first European Champion Clubs Cup was played in season 1955/56 with sixteen clubs from Europe. In the years the tournament suffer a lot of transformations and these days it has the following structure. Preliminary round – 4 clubs, three qualification rounds, following by play-off round, group stage with 32 clubs and knockout stage – 16 clubs. Each club enters in any of the rounds according to UEFA national association ranking and position won during his country football season.
- Preliminary round is built by 4 clubs – champions from national associations ranked from 52nd to 55th place.
- First qualifying round – thirty three champions from national associations ranked from place 18 to 51 plus the winner of previous round.
- In Second qualifying round enters 3 champions clubs from national associations ranking from 15th to 17th, six clubs which finished in second place from national association ranking from place 10th to 15th and seventeen winners of First qualifying round – total 26 clubs.
- Third qualifying round contains 20 clubs – 2 champions from national associations ranked 13th and 14th, 3 runners-up from national associations ranked 7th to 9th and 2 clubs finished on 3rd place from national associations 5th and 6th plus 13 winner of second qualifying round.
- Play-off phase contains 12 clubs – 2 champions clubs from national associations ranked 11th and 12th plus 10 clubs advancing from previous stage.
- Group round contains 32 clubs – 10 champions from national associations ranked by UEFA on place 1st to 10th, 6 clubs finished 2nd from national associations ranked 1st to 6th, 8 clubs finished on third and fourth place from national associations ranked 1st to 4th, 2 clubs won UEFA Champions League and UEFA Europa League previous season plus 6 clubs advanced from previous round.
- Knockout round is built by 16 clubs which are clubs finished on 1st and 2nd place in group round.
The clubs with the most titles won is Real Madrid with 13 titles, followed by Milan with 7 titles. Third place is divided by Bayern Munich, Liverpool and Barcelona – 5 titles each.