French designer Louis Réard, a former automotive engineering who worked for his mother’s lingerie business, inspired the modern bikini at a time when showing the navel was novel.

By the summer of 1946, Hollywood icons and pinup models had worn two-piece suits, but that last inch of midriff was fashion’s final “zone of contention,” said Kelly Killoren Bensimon, who recorded a history of the garment in “The Bikini Book.”

“We had seen Jayne Mansfield and a lot of other actresses wearing two-piece bathing suits,” Bensimon said in an interview. “But never with the navel showing.”

Réard designed the bikini after his rival, Jacques Heim, claimed success with a design he called “the Atom.” Réard stitched together a napkin’s worth of newsprint-patterned fabric and achieved something smaller than Heim’s Atom. Réard named the garment after the Bikini Atoll, the remote island where atoms were being split in atomic bomb tests.

Then, a week before Bastille Day and in the midst a global textile shortage, Réard had a poolside photo shoot in Paris. Micheline Bernardini, a 19-year-old nude dancer from the Casino de Paris, agreed to don Réard’s bikini. She put on the four small patches Réard had strung together and showed the fashion world the female belly button.

The day was July 5, 1946. Europe had just emerged from World War II, and Parisians were enjoying the season of freedom.

At first, the bikini was more of a sensation than a success. Some photographers and models did dare to shoot the suits, and Réard built his own business around the design.

But it was slow to break through the modesty barriers on European beaches, much less in the postwar United States. Many commentators condemned the look, and plenty of communities banned it. Even today, the swimsuit is the center of debate in some Western locales; Barcelona banned wearing a bikini on the streets in 2011.

Six years after Bernardini became the first girl in a bikini, Bridgette Bardot starred in “The Girl in the Bikini.” In 1962, Ursula Andress strode from the surf in “Dr. No” in nothing but a knife and bikini as the original Bond girl.

Ursula Andress wore a bikini in the 1962 James Bond movie “Dr. No.” (AP)
Ursula Andress wore a bikini in the 1962 James Bond movie “Dr. No.” (AP)

It was the Jet Age that really boosted the fortunes of the skimpy garment, according to Bensimon. The wealthy and glamorous began to shuttle in and out of the Riviera, bringing new standards of beachwear to shores — and soon pools — around the world.

In the United States, it took a former Mousketeer to make the big reveal okay for family viewing, Bensimon said. When Annette Funicello, a child star from the Mickey Mouse Club, got permission to wear a bikini in most of her madcap beach movies, “everybody noticed,” Bensimon said.

“She just wanted to be one of the cool kids,” the author added.

So did many of the kids who saw her. By then, America’s top-to-bottom adoption of the bikini was irreversible.

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Fanny packs, prairie dresses and luxury shower shoes