Founded in 1945 by University of Chicago scientists who had helped develop the first atomic weapons, the Bulletin of the Atomic Scientists created the Doomsday Clock two years later to convey the urgency of threats to humanity and the planet. The decision to move (or to leave in place) the minute hand of the clock is made every year by the Bulletin’s Science and Security Board in consultation with its Board of Sponsors, which includes seventeen Nobel laureates. When the clock debuted in 1947, it was set at seven minutes to midnight. In 1953, when the US and the Soviet Union began testing hydrogen bombs, it was moved to its most extreme position to date—two minutes to midnight. In 1991, after the two countries signed the Strategic Arms Reduction Treaty, the clock was set to seventeen minutes to midnight. In 2015, after three years of remaining at five minutes before midnight, the clock was moved ahead two minutes as a result of “unchecked climate change, global nuclear weapons modernizations, and outsized nuclear weapons arsenals.”