Doomsday Clock: What is Doomsday Clock which is telling the time of destruction of the world?

The Doomsday Clock board said, “Russia’s threats to use nuclear weapons remind the world that escalating conflict by accident, intent or miscalculation is a terrible risk.” The less time remains in the Doomsday Clock before it is midnight, the closer is the danger of catastrophe in the world. Only 90 seconds away from coming to the brink of the end of the world this year. (Photo- thebulletin.org/doomsday-clock)