It was in the area of beachwear that the most revolutionary clothing invention of the 1950s - the bikini - was created. Simply defined, the bikini is an abbreviated two-piece swimsuit with a bra top and bottoms cut below the navel. Broadly defined, the bikini represented a giant social leap involving body consciousness, moral concerns, and sexual attitudes, and pre-empted all that the revolutionary sixties had in store.

Right: Micheline Bernardini models the world’s first bikini, in 1946

Fashion designer Jacques Heim and mechanical engineer Louis Reard both claim to be the first to launch the timeless timeless two-peice on the French Riviera in Cannes in the summer of 1946. The suit's design consisted of two triangles on top, positioned to cover the chest and two triangles, one front, one back, on the bottom. Since it was Reard who first patented his version of the bikini, Heim is often forgotten, however there is still much debate over who was the actual inventor. A likely scenario is that both men had seen the local young women of Cannes, France sunning themselves in abbreviated swimsuits in order to achieve the darkest tan while pushing the fashion to the acceptable social limit. The first time the bikini appeared in a fashion event was at a 1946 poolside fashion show in Paris. Reard's original bikini was so small that no Parisian models at the time would wear it on the runway. He had to hire a nude dancer from the Casino de Paris to wear it in its first unvieling on the catwalk.

The bikini was named after a few small South Pacific islands called Bikini Atoll, where the United States were conducting nuclear bomb tests. This coincided with the U.S. Government's wartime rationing, which had ordered a 10 percent reduction of fabric in the manufacture of garments - according to Heim, his skimpy swimsuits were just what Uncle Sam ordered!
Though the bikini was a success in postwar France, the traditional Catholic countries of Spain, Portugal and Italy, banned the bikini. Americans, too, deemed the bikini too risque until Hollywood stars were photographed wearing them. Decency leagues pressured Hollywood to keep it out of feature films, but movie fans caught on quickly and replicated the look of the stars like Brigitte Bardot, futhering the popularity of the bikini.

In 1951 bikinis were banned from the Miss World Contest following the crowning of Miss Sweden in a bikini and subsequent protests with a number of countries threatening to withdraw. In 1957, however, Brigitte Bardot's bikini in And God Created Woman created a market for the swimwear in the US, and in 1960, Brian Hyland's pop song "Itsy Bitsy Teenie Weenie Yellow Polka Dot Bikini" inspired a bikini-buying spree. In 1962, an icon was born as Bond Girl Ursula Andress emerged from the sea wearing a white bikini in Dr. No. Finally the bikini caught on, and by 1963, the movie Beach Party, starring Annette Funicello (emphatically not in a bikini, by mentor Walt Disney's personal request) and Frankie Avalon, led a wave of films that made the bikini a pop-culture symbol.

The sex appeal of the apparel prompted numerous film and television productions as soon as public morals changed to accept it. They include the numerous surf movies of the early 1960s and the television series, Baywatch. Iconic portrayals of bikinis in movies include Ursula Andress as Bond girl Honey Ryder in Dr. No (1962), Raquel Welch as the prehistoric cavegirl in the 1966 film One Million Years B.C., and Phoebe Cates in the 1982 teen film Fast Times at Ridgemont High. These scenes were recently ranked 1, 86, and 84 in Channel 4 (UK)'s 100 Greatest Sexy Moments (in film) respectively.

In addition, a variant of the bikini popular in fantasy literature is a bikini that is made up of metal to serve as (admittedly rather impractical) armour, sometimes referred to as a "chain mail bikini" or "brass bikini"; the character Red Sonja is a famous example. A term for such usage, where sex appeal is more important than actual practicality, is babes-at-arms (parodying "men-at-arms" for fully armoured soldiers). In science fiction, Star Wars Episode VI: Return of the Jedi features the notable "Princess Leia's metal bikini" costume, that is worn by the character Princess Leia when she is held captive at the film's beginning. This particular "bikini" has since been elevated to pop culture icon status, spawning various spoofs and parodies (most notably the episode of Friends, The One with the Princess Leia Fantasy) and even a dedicated fansite, Leia's Metal Bikini.

French film star Brigette Bardot was the focus of atention modelling the bikini in 1961 on the beach at Cannes, on the French Riviera

Fashion designer, Rudi Gernreich has been credited with introducing the first thong bikini in 1974. Another reference states that thongs, originally called tangas, first hit the beaches of Brazil in 1977. Many fashion historians, however,  believe that the thong first appeared in the 1939 World's Fair. New York Mayor Fiorello LaGuardia ordered the city's nude dancers to cover themselves and the thong was invented to just barely do the job.
Thong underwear and swimwear is a style characterized by a thin strip of material along the center of the garment's rear designed to sit between the wearer's buttocks connecting the front or pouch to the waistband behind the wearer. Thongs come in a variety of styles depending on the thickness, material, or type of this rear portion of fabric and are available for both men and women throughout the world. Thongs are similar to g-strings, the main difference being that thongs have more material between the legs and back whereas a g-string has less, usually an actual "string" of material.