The surface on which tennis is played is rectangular in shape and flat. A tennis court is 78 feet (23.77 metres) long and 27 feet (8.23 metres) wide for singles matches, and for doubles matches, the width increases to 36 feet (10.97 metres). There is always a little bit of additional space, which is left clear and vacant for the players to reach out for overrun balls. The net, which is stretched across the full width of the court, divides the tennis court into two equal parts and is parallel to the baselines. The net is three-and-a-half feet (1.07 metres) high at the two posts, and three feet (914 millimetres) high in the centre. The part of the court on the right side of each player is called the deuce court, and that on the left of each player is called the ad court. Tennis courts are usually made of grass (Wimbledon is played on grass courts), clay (the French Open is played on clay courts) or concrete, as in the case of a hard court (the Australian Open and the U.S. Open, the first and last Grand Slam events of the year, are played on hard court surfaces).
