In tennis, grass is grown on very hard-packed soil, and bounces may vary depend on how healthy the grass is, how recently it has been mowed, and the wear and tear of recent play. The most famous grass tennis court in the world is Centre Court at Wimbledon. Tennis, however, is generally played on clay courts, and only a a small number of regular tennis tournaments are played on a grass court. The exterior is less firm than rigid courts, causing the ball to spring back lower, and so players must reach the ball quicker. Due to high maintenance costs however, grass courts are now rare as they must be watered and mowed often, and take a longer time to dry after rain than hard courts.