Widely considered to be one of the greatest tennis players of all time, Martina Navratilova amassed a record number of singles and doubles title wins, while becoming the greatest Grand Slam champion of all time. Born on Oct. 18, 1956 in Prague, Czechoslovakia, Navratilova was three years old when her parents divorced. Her mother remarried to Miroslav Navrátil, who became her first tennis coach. In 1972, she won the Czechoslovakian national championship at 15 years old and the following year debuted with the United States Lawn Tennis Association tour, but did not turn pro until she was 17. After winning her first pro title, she began appearing in Grand Slam tournaments, losing the finals of the Australian Open in 1975 and the French Open to career rival Chris Evert that same year. When she was 18, Navratilova defected from Czechoslovakia and received her green card. From there, she won her first of nine Wimbledon titles in 1978, defeating Evert in three sets and becoming the No.1 female tennis player in the world. She defended her title in 1979 and went on to capture other Grand Slam tournaments, winning her first of three Australian Opens in 1981, her first French Open in 1982, and her first U.S Open in 1983, defeating Evert in two of the three.