 Betty Grable and Marilyn Monroe were two of the most popular pinup models.In the second half of the 20th century, pornography evolved into the men's magazines such as "Playboy" and "Modern Man" of the 1950s.In fact, the beginning of the modern men's glossy magazine (or girlie magazine) can be traced to the 1953 purchase by Hugh Hefner of a photograph of Marilyn Monroe to use as the centerfold of his new magazine "Playboy".