The most powerful sisters in sports are also boundary-breakers. Venus and Serena Williams became professional tennis players in 1994 and 1995 respectively and within a decade become two the top female tennis players in the world. Venus was the first African American to be named the No. 1 in singles by the Women’s Tennis Association. The sisters are also successful off the court as Serena is heavily into charity with at-risk youth while Venus is a fashion and design entrepreneur.