Claim: Tennis is an activity.

Tennis is a racket sport that can be played individually against a single opponent -LRB- singles -RRB- or between two teams of two players each -LRB- doubles -RRB- . Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball covered with felt over or around a net and into the opponent 's court . The object of the game is to play the ball in such a way that the opponent is not able to play a valid return . The player who is unable to return the ball will not gain a point , while the opposite player will .   Tennis is an Olympic sport and is played at all levels of society and at all ages . The sport can be played by anyone who can hold a racket , including wheelchair users . The modern game of tennis originated in Birmingham , England , in the late 19th century as `` lawn tennis '' . It had close connections both to various field -LRB- `` lawn '' -RRB- games such as croquet and bowls as well as to the older racket sport of real tennis . During most of the 19th century , in fact , the term `` tennis '' referred to real tennis , not lawn tennis : for example , in Disraeli 's novel Sybil -LRB- 1845 -RRB- , Lord Eugene De Vere announces that he will `` go down to Hampton Court and play tennis . ''   The rules of tennis have changed little since the 1890s . Two exceptions are that from 1908 to 1961 the server had to keep one foot on the ground at all times , and the adoption of the tiebreak in the 1970s . A recent addition to professional tennis has been the adoption of electronic review technology coupled with a point challenge system , which allows a player to contest the line call of a point , a system known as Hawk-Eye .   Tennis is played by millions of recreational players and is also a popular worldwide spectator sport . The four Grand Slam tournaments -LRB- also referred to as the `` Majors '' -RRB- are especially popular : the Australian Open played on hard courts , the French Open played on red clay courts , Wimbledon played on grass courts , and the US Open played also on hard courts .