Born in Prague, Martina Navratilova wanted to conquer the tennis world, and she knew she had a better shot at doing that in the U.S. than in communist Czechoslovakia. “The [Czech] tennis federation did not let me play the tournaments I wanted to play,” she says, noting that it routinely denied her visas to tournaments in the West. So during the 1975 U.S. Open, American authorities helped her defect, the Czech government subsequently stripped her of her citizenship, and she went on to dominate women’s tennis, winning 18 Grand Slam singles titles. She holds the record for career titles (167), consecutive Wimbledon singles titles (6) and Grand Slam doubles titles (31). Her unprecedented off-court training program and dietary regime raised the bar for everyone and helped her bring down barriers of ageism. In 2003 she became the oldest-ever Grand Slam champion by winning the women’s doubles at Wimbledon at age 46.