Those heading to the semis or the finals of the U.S. Open will see a celebration of a landmark event in addition to great tennis.

It’s been 50 years since the U.S. Open became the first major tennis event to offer equal pay for men and women.

Hall of Famer Billie Jean King led the charge in 1973, becoming a pioneer for women’s rights.

King’s face is featured on posters, banners and scoreboards at the tennis center to celebrate the 50th anniversary of equal pay.

Longtime tennis fans say the celebration has been great.

The Women’s Tennis Association said last month that it wants equal pay at all events featuring men and women by 2033. Discussions are underway to make that happen.