Like sister Venus, Serena has been on the tennis scene for decades, racking up the championships and accolades to become an all-time great. With 23 Grand Slam singles titles and counting, she has the most titles of the Open era (and is only one shy of the all-time record). She also has four Olympic gold medals and 14 Grand Slam doubles titles, along with a slew of other records, including being the only player ever to achieve a "Golden Slam" — winning all four majors and a gold medal in a single year — in both singles and doubles.