The Champions League is the premier club competition in Europe. It’s a tournament that has crowned champions in every era and is watched by millions of fans around the world.

The competition has been around for more than half a century now, and it’s been through a lot of changes in the way that clubs compete with each other. The competition has grown in size, the number of teams that qualify for the knockout stages has swelled, and the way that matches are played has evolved over time.

For 21 seasons, the Champions League had a group stage in which 32 teams were split into eight groups of four. The winner and runner-up from each group advanced to the quarterfinals, semifinals and final of the competition.

From the 2024-25 season onwards, the tournament has a revamped format that removes the group phase altogether. The competition now has a league stage with 36 qualified teams playing each other twice through January, using a seeding system that creates balanced schedules.

The top eight clubs advance to the round of sixteen, while the bottom twelve teams are eliminated. The ninth through twenty-fourth ranked teams participate in a play-off round, with the winning team earning one of the remaining seven qualifying spots for the next round. In addition, the champions from leagues with higher coefficients get automatic qualification and a bye to the last 16 of the competition. The remaining slots are awarded to teams that finish second through fourth in their national leagues.