Talk about trailblazers - Billie Jean almost single-handedly lifted women's professional tennis – and indeed women's sports in general – to today's level. While she was at it, she took home 12 Grand Slam singles titles and a career Grand Slam.

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Serena Williams (r.) holds the Billie Jean King cup presented by Billie Jean King (c) after Williams beat her sister Venus, holding the consolation trophy, to win the BNP Paribas Showdown tennis match at Madison Square Garden in New York March 2, 2009.