Serena Williams will apparently end her extraordinary tennis career shortly. The 40-year-old, 23-time Grand Slam winner interpreted this on Instagram and in an article in the magazine Vogue on. “There are moments in life when you have to choose to go in a different direction,” the American wrote next to a picture of the September issue Voguewhose cover she adorns: “My goodness, I enjoy tennis. But now the countdown has begun.”