Tennis has an estimated global following of 1 billion fans and a global sphere of influence. Different versions of the sport are believed to have been played by the Egyptians, Romans and the Greeks, although the modern sport was first popularized in France. From France, it spread to other parts of Europe and eventually to the whole world. The sport is played by two teams of either one or two players each and involves bouncing a ball over a net by use of tennis rackets. Points are earned when the opponent does not throw back the ball in the predetermined dimensions of the rectangular court.