Tennis is a sport played between two players (singles) or between two teams of two players each (doubles). Each player uses a strung racquet to strike a hollow rubber ball covered with felt (most of the time Optic Yellow, but can be any color or even two-tone) over a net into the opponent’s court. The modern game of 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 tiebreaker in the 1970s, the rules of tennis have changed very little since the 1890s. A recent addition to professional 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 worldwide follow tennis as a spectator sport, especially the four Grand Slam tournaments (sometimes referred to as the “majors”): the Australian Open, the French Open, Wimbledon, and the US Open. Tennis as the modern sport can be dated to two separate roots. Between 1859 and 1865, Major Harry Gem and his friend Augurio Perera developed a game that combined elements of rackets and the Basque ball game pelota, which they played on Perera’s croquet lawn in Birmingham, United Kingdom. In 1872, along with two local doctors, they founded the world’s first tennis club in Leamington Spa. The Courier of July 23, 1884 recorded one of the first tennis tournaments, held in the grounds of Shrubland Hall.
In December 1873, Major Walter Clopton Wingfield designed a similar game — which he called sphairistike (Greek: σφάίρίστική, meaning “skill at playing at ball”), and was soon known simply as “sticky” — for the amusement of his guests at a garden party on his estate of Nantclwyd, in Llanelidan, Wales. He based the game on the newer sport of outdoor tennis or real tennis. According to most tennis historians, modern tennis terminology also derives from this period, as Wingfield borrowed both the name and much of the French vocabulary of real tennis and applied them to his new game.
The first championships at Wimbledon in London were played in 1877. On May 21, 1881, the United States National Lawn Tennis Association (now the United States Tennis Association) was formed to standardize the rules and organize competitions. The U.S. National Men’s Singles Championship, now the US Open, was first held in 1881 at Newport, Rhode Island. The U.S. National Women’s Singles Championships were first held in 1887. Tennis was also popular in France, where the French Open dates to 1891. Thus, Wimbledon, the US Open, the French Open, and the Australian Open (dating to 1905) became and have remained the most prestigious events in tennis.Together these four events are called the Grand Slam (a term borrowed from bridge).
