The Davis Cup is the premier international team event in men's tennis. The largest annual international team competition in sport, the Davis Cup is run by the International Tennis Feeration (ITF) and is contested between teams of players from competing countries in a knock-out format. The competition began in 1900 as a challenge between the United States and Great Britain. In 2005, 134 nations entered teams into the competition. The most successful countries over the history of the tournament are the United States (winning 32 tournaments and finishing as runners-up 29 times) and Australia (winning 23 times and finishing second 18 times and also winning on four occasions with New Zealand under the name 'Australasia').