The period of prosperity following World War I brought a marked increase in the appreciation of recreation, resulting in an increase of swimming pools and available beaches. Indoor pools, which made swimming a year-round activity, were becoming even more numerous than beaches. Swimming was now established as a sport and a recreation for both men and women. According to a 1924 magazine article in the _Delineator_, seldom was a swimming meet held anywhere in the country without events for women. At Palm Beach, however, one of the few remaining citadels of "high society," an axiom of fashion dictated that a lady or gentleman not go into the water before 11:45 in the morning; should one do so, one ran the risk of being taken for a maid or valet. The masses, however, swam for pleasure without regard to the inhibitions of high fashion. This period was also marked by the advent of swimming personalities of both sexes. Johnny Weissmuller became a popular hero for his accomplishments in competitive swimming from 1921 to 1929. Even before the war Annette Kellerman, star of vaudeville and movies, had become famous for her fancy diving as well as her celebrated figure, which she daringly exhibited in a form-fitting, one-piece suit. In addition to writing an autobiography, she authored articles and a swimming instruction book for women. As an example of what exercise, including swimming, could do for women, Annette Kellerman also lent her name to a course of physical culture for less "well-developed" ladies. Another product of this new age of recreation was Gertrude Ederle, who learned to swim at the Woman's Swimming Association of New York. She rose to sudden fame in 1926 as the first woman to swim the English Channel. As previously stated, swimming was practiced through the Middle Ages as a useful skill for men. Gradually this activity became regarded as also a healthful exercise and then as a recreation. Finally by the late 19th century swimming also had achieved the status of a competitive sport--but for men only. It was not until the 1920s that social attitudes permitted women the same full use of the water as men. The restrictive attitudes defining women's proper behavior in the water prior to the 1920s were one element of the mores defining women's participation in society. Thus as more liberal attitudes gained acceptance and modified the original concept of the "weaker sex," women gradually achieved social acceptance of their full participation in aquatic activities. Bathing Costume Bathing became popular as a medicinal treatment for both men and women of the new world in the last half of the 18th century. It was the only aquatic activity, however, that was considered proper for women until over a hundred years later.