On July 5, 1946, a French engineer called Louis Réard unveiled an outfit "smaller than the world's smallest swimsuit." It arrived with a bang, so named after the nuclear tests at Bikini Atoll, and remains popular to this day
Contrary to popular belief, the bikini was actually an ancient invention, as illustrated by this 4th century Roman mosaic from Villa Romana Del Casale in Sicily, Italy. Going back even further, two-piece garments were worn by women (for athletic purposes) as early as 1400 B.C. and are depicted on Greek urns and paintings from that period.
A dressing room on wheels was considered essential for preparing for a swim at Europe's beaches in the 1890s. Ladies would sew weights into the hems of their garments to prevent them from riding up and showing their legs.
Loud and Proud
Layers of petticoats eventually gave way to a single-piece costume that no longer hid the contours of the female body. The precursor to the modern bikini emerged in 1907, when Australian swimmer and performer Annette Kellerman (not pictured here) was arrested on a Boston beach for wearing a formfitting one-piece.
Fleshing It Out
During the 1940s, fashion houses pushed the boundaries of bathing suits, exposing considerably more flesh than ever before. War rationing provided the stimulus for the two-piece, when the U.S. government ordered manufacturers to reduce the amount of fabric they used, resulting in the bare midriff. But it would be a Frenchman sitting on a beach in the South of France who worked out that there was money to be made from navel-gazing .
On July 5, 1946, French engineer Louis Réard designed a garment "smaller than the world's smallest bathing suit." Four days earlier, the U.S. military had conducted nuclear tests at Bikini Atoll. Réard hoped that his invention would be as explosive as that test and so called his new creation the bikini. But at first none of the Parisian models would dare to wear his design.
The Original Itsy-Bitsy Girl
Micheline Bernardini, a nude dancer, was the first woman ever to wear a bikini, during a July 11, 1946, showing for the press at the fashionable Piscine Molitor in Paris. The bikini was so small it could fit into a matchbox, like the one she's holding. Unsurprisingly, Bernardini received plenty of fan mail.
It's a Sin
Bikinis were banned from worldwide beauty pageants after the first Miss World Contest in London in 1951. As the tasteful one-piece continued to reign supreme, the bikini was later also banned in Belgium, Italy, Spain and Australia, and it was even declared sinful by the Vatican.
And God Created Bardot
Movie star Kirk Douglas frolics on a Cannes beach with the young French actress Bridget Bardot, who was widely credited with popularizing the bikini. It's been said that Bardot did more for France's international trade balance than the entire French car industry.
An iconic moment in cinema history came in 1962, when Swiss actress Ursula Andress, playing Honey Rider in the James Bond film Dr. No, strode out of tropical Caribbean waters wearing her home-made bikini. Nearly 40 years later, it sold for $60,000 at an auction in 2001. The following year, the moment was memorably re-created by Halle Berry in Die Another Day.
Raquel on the Rocks
Actress Raquel Welch poses in that legendary cavewoman bikini for a publicity shot for her 1967 movie One Million Years B.C. By this point, many famous actresses had donned the bikini — including Marilyn Monroe, Jayne Mansfield and, of course, Bardot.
TIME's sister publication published its first ever swimsuit issue back in 1964. The story behind this debut has it that editor Andre Laguerre could find no compelling sporting events to write about during the winter months and asked fashion reporter Jule Campbell to help fill some space, including the cover, with a model. She found Babette March, above, and the rest is history.
Having a Ball
The U.S. professional-volleyball player (and model) Gabrielle Reece promotes her sport in 1997. Her team took first place at the first ever Beach Volleyball World Championships, but she's probably now best known for her work on television.
Life's a Beach
Perhaps the quintessential bikini photo, two women in string bikinis, or tangas, walk along Rio de Janeiro's Ipanema Beach in Brazil. To try to sum up the appeal of the bikini, TIME asked Dominic Smith, editor of U.K. men's magazine Nuts for an appraisal: "In the austere postwar years, mankind needed something to bring peace and happiness to the planet once more. That thing was the bikini. Its perfection of form and function ensured that once again, mankind was united in a single thought: phwoar! Happy 63rd birthday, bikini — possibly the greatest enjoyment-giving invention of the 20th century."