The French sports daily L'Equipe were the first champions of the cause for a European-wide club competition. The original tournament did not stipulate that the participating teams had to be champions of their country, but they invited clubs who they considered had the most fan appeal.
With the current Champions League format as many as four or even five teams might represent each country thus ensuring the bigger teams still participate even if they don't win their respective domestic leagues.
The format changed in the 1992/1993 season when a group phase was added to the traditional knockout.
In 2005, one of the greatest comebacks in any tournament saw Liverpool come from three goals down to draw with AC Milan after 120 minutes of football. They then won their 5th European Cup on penalties thanks to some inspired goalkeeping.