When Billie Jean King won the 'Battle of the Sexes'

Fifty years ago, Billie Jean King defeated Bobby Riggs in a historic "Battle of the Sexes" tennis match.

It was the most watched tennis match of all time, with an estimated 90 million people tuning in worldwide, and it became an important moment in the women's rights movement.

Riggs, a cocky 55-year-old once ranked No. 1 in the world, claimed he could still beat the top female players in the game even though he was much older. And months before taking on King, he defeated 30-year-old star Margaret Court in straight sets 6-2. 6-1.

After his win over Court, Riggs challenged King, a 29-year-old champion who established the women's tour that year and threatened to boycott the US Open if male and female champions did not receive the same prize money. She accepted Riggs' challenge and was determined to stand up for women worldwide.

"I thought it would set us back 50 years if I didn't win that match," King said. "It would ruin the women's tour and affect the self-esteem of all women."

The match took place at the Astrodome in Houston on September 20, 1973. More than 30,000 people were in attendance. King won in straight sets — 6-4, 6-3, 6-3 — and took home the $100,000 prize money. But the real prize was what it meant for women's sports and the fight for equality.