Defining a great football team is not as easy as it sounds. It can be quite subjective, in that some value trophy success as the be all and end all when it comes to measuring the greatness of a football team, whereas others would argue that the beauty or innovative nature of a football team is what separates a successful side from a truly great era-defining team. Our opinion is that a great team can be either but in general tends to be a team that can combine both qualities, successful as well as innovative, and in very rare cases capable of producing breathtaking football to boot. In this category we have the greatest national sides of all time - generally teams that have won the World Cup or European Championships, or who have made a immeasurable impact on a international tournament and are still remembered today for the attractive style of football they played and the teams that have revolutionised football through their performances in the international arena. Similarly in this category there are also the greatest club sides of all time; teams that have transcended success within their domestic league. They are either European sides that have won the European Cup more than once, or won and the reached the Final several times, with largely the same team, management and system. Or they may have won the trophy once but done so in some style or significance. The list also includes South American teams that have won the Copa Libertadores several times with largely the same side and have also beat the European Champions in the Inter-Continental Cup.