Day Of The Underwear, New York City, United States

A Russian immigrant named Ida Rosenthal further developed the brassiere in this decade when she introduced modern cup sizes in 1928 for her company, Maidenform.
• 1930s and 1940s
Modern men's underwear was largely an invention of the 1930s. On 19 January 1935, Coopers Inc. sold the world's first briefs in Chicago. Designed by an "apparel engineer" named Arthur Kneibler, briefs dispensed with leg sections and had a Y-shaped overlapping fly. The company dubbed the design the "Jockey" since it offered a degree of support that had previously only been available from the jockstrap. Jockey briefs proved so popular that over 30,000 pairs were sold within three months of their introduction. Coopers, having renamed the company Jockey, sent its "Mascul-line" plane to make special deliveries of "masculine support" briefs to retailers across the US. In 1938, when Jockeys were introduced in the UK, they sold at the rate of 3,000 a week.
In this decade, companies also began selling buttonless drawers fitted with an elastic waistband. These were the first true boxer shorts, which were named for their resemblance to the shorts worn by professional fighters. Scovil Manufacturing introduced the snap fastener at this time, which became a popular addition to various kinds of undergarments.