The Doomsay Clock is a symbolic clockface maintained since 1947 by the Board of Directors of the Bulletin of the Atomic Scientists at the University of Chicago. It uses the analogy of the human race being at a time that is "minutes to midnight" where midnight represents "catastrophic destruction". The analogy originally represented the threat of global nuclear war, but has since evolved to include nuclear weapons, climate-changing technologies and "new developments in the life sciences and nanotechnology that could inflict irrevocable harm." Since its introduction, the clock has appeared on the cover of each issue of the Bulletin of the Atomic Scientists. The first representation of the clock was produced in 1947, when artist Martyl Langsdorf, the wife of physicist, Alexander Langsdorf, Jr., who worked on the Manhattan Project, was asked by magazine cofounder Hyman Goldsmith to design a cover for the June issue.