October 4, 2015 - Gary M. Prior/Hulton Archive more pics like this »
Steffi Graf
Steffi Graf is the first and only tennis player to ever complete a Golden Slam, which means she won all four Grand Slam titles, as well as a gold medal in singles at the Olympic Games, all in one year. She achieved that accomplishment in 1988, and no tennis player, male or female, has joined her in those ranks since.