The modern bikini rose to prominence in 1946 as a result of gradual shifts in cultural attitudes and fashions from the 1910s through the 1940s. The modern design is credited to French designer Louis Reard, who named his creation after the Bikini Atoll, the testing ground of the atomic bomb.
After female swimming was introduced into the Olympics in 1912, designer Carl Jantzen made the first working two-piece swim suit. Soon after came the first "swim suit day" in Madison Square Garden in New York. In the 1920s, in line with the slowly expanding liberation of women, women's swimsuit designs became tighter and more decorative. The 1930s and 1940s saw shrinking neck lines, disappearing sleeves and straps that enabled shoulder tanning. The passage of time also ushered in more midriff exposure, although this type of swimwear was considered indecent anywhere besides the beach.
The development of the bikini was greatly accelerated by the Second World War. Wartime rationing of cotton, silk, nylon, wool and rubber meant a forced 10 percent decrease in the amount of fabric used in swimsuits. When the atomic bomb dropped, effectively ending the war, it ushered in a new cultural era in which changing norms turned the once unthinkable--including the bikini--into reality.