The Grand Slam tournaments, also called majors, are the four most important annual tennis events. They offer the most ranking points, prize money, public and media attention, the greatest strength and size of field, and greater number of "best of" sets for men. The Grand Slam itinerary consists of the Australian Open in mid January, the French Open in May and June, Wimbledon in June and July, and the US Open in August and September. Each tournament is played over a period of two weeks. The Australian and United States tournaments are played on hard courts,[a] the French on clay, and Wimbledon on grass. Wimbledon is the oldest, founded in 1877, followed by the US in 1881, the French in 1891, and the Australian in 1905. However, of these four, only Wimbledon was a major before 1924/25, the time when all four became designated Grand Slam tournaments. Skipping Grand Slam tournaments—especially the Australian Open because of the remoteness, the inconvenient dates (around Christmas and New Year's Day) and the low prize money—was not unusual before 1982, which was the start of the norm of counting Grand Slam titles.