Serena Williams is one of the richest athletes in the world, betcha didn't know how that money got served up

Serena Williams is one of the richest athletes in the world, but women in tennis didn’t always command big pay days. In fact, men used to get paid double the amount of women. Billie Jean King changed the game in 1973 when she led the formation of the Women’s Tennis Association and made the case for equal pay. The U.S. Open officially became the first Grand Slam to offer equal prize money for both men and women.