How does the UEFA Champions League work?

The UEFA Champions League is a prestigious annual soccer competition in Europe. It involves top clubs from different European countries competing against each other in a series of matches. The tournament starts with a group stage where teams are divided into groups and play against each other. The top teams from each group advance to the knockout stage, where they play home-and-away matches until a winner is determined in the final. The winning team is crowned the champion of Europe.