The T- Shirt is so-called because of its shape, which resembles the letter T when lying flat and is first cited in America from c. 1920. Before then, they were known as vests and looked upon as underwear, routinely worn by the military of many nations. After WWI, T-shirts were typically worn by American farm workers. They soon ceased to be viewed as underwear and were fast becoming the garment of choice for American youth. During WWII, newsreels showed US troops in the Pacific in their olive drab T-shirts. This gave impetus to the trend, which was well established worldwide by 1950.