Yes, October 21 is Wonder Woman Day, in honor of the superheroine created William Moulton Marston, writer, psychologist, and inventor of the prototype of the lie detector.
Marston was hired in late 1940 to create his own new superhero by the folks at the company now known as DC Comics. He'd already invented the polygraph and wanted this new hero to be one who would win not through violence but with love.
"Fine," his wife, Elizabeth, also a psychologist, agreed. "But make her a woman."
Marston, inspired by his wife and their life partner, Olive Byrne, modeled and created Wonder Woman, civilian name Diana Prince, from them. The superheroine debuted October 21, 1941, in All Star Comics and later became the star of her own title.
"Not even girls want to be girls so long as our feminine archetype lacks force, strength, and power," he once said. "Not wanting to be girls, they don't want to be tender, submissive, peace-loving as good women are. Women's strong qualities have become despised because of their weakness. The obvious remedy is to create a feminine character with all the strength of Superman plus all the allure of a good and beautiful woman."
The outspoken feminist described bondage and submission as a "respectable and noble practice" and in those early Wonder Woman years, there is no lack of very visual representation of binding in the panels.
Quite likely, Diana is the first bisexual super hero, because beyond the queerness of her inspiring forebears, Diana comes from the mythical island of Themyscira, also known as Paradise Island, an island that holds only women. And while marriage is known there, there are no men. No one bats an eye.
It's in 2016 in the comics that Wonder Woman writer Greg Rucka puts her bisexuality front and center on the page. As he said to CBR, "It's supposed to be paradise. You're supposed to be able to live happily. You're supposed to be able -- in a context where one can live happily, and part of what an individual needs for that happiness is to have a partner -- to have a fulfilling, romantic and sexual relationship. And the only options are women. ... But an Amazon doesn't look at another Amazon and say, 'You're gay.' They don't. The concept doesn't exist."
For the actresses who have played her over the years, in both live-action and animated form, there's no issue with that.