American professional tennis player Serena Williams has won over 20 Grand Slam singles titles and several Olympic gold medals. Born in 1981 in Saginaw, Michigan, Serena Williams began intensive tennis training at age 3. She won her first major championship in 1999 and completed the career Grand Slam in 2003. Along with her individual success, Williams teamed with sister Venus to win a series of doubles titles. Her victory at Wimbledon in 2015 made her the oldest Grand Slam singles champion in the Open era.