Tennis

Tennis is a game played between two players (singles) or between two teams of two players (doubles). Each player uses a strung racquet to strike a hollow rubber ball covered with felt (most of the time yellow,[1] but can be any color or even two-tone) over a net into the opponent's court.
Tennis originated in the United Kingdom in the late 19th century as "lawn tennis" and had heavy connections to the ancient game of real tennis. After its creation, tennis spread throughout the upper-class English-speaking population before spreading around the world. Tennis is an Olympic sport and is played at all levels of society at all ages. The sport can be played by anyone who can hold a racket, including people in wheelchairs. In the United States, there is a collegiate circuit organized by the National Collegiate Athletics Association.
Except for the adoption of the tie-breaker in the 1970s, its rules have remained remarkably unchanged since the 1890s. A recent addition to tennis has been the adoption of "instant replay" technology coupled with a point challenge system which allows a player to challenge the official call of a point.
Along with its millions of players, millions of people world-wide follow tennis as a spectator sport, especially the four Grand Slam tournaments: Australian Open, French Open, Wimbledon, and the U.S. Open. The growth of tennis in Eastern Europe and the Far East has been especially notable in recent years.