The Bulletin of Atomic Scientists announced Tuesday that the "Doomsday Clock" is now set to 89 seconds to midnight.

Iconic Doomsday Clock moves one second closer to midnight as global existential threats rage. Clock factors include nuclear weapons, climate crisis, artificial intelligence, infectious diseases, and conflicts in Ukraine and the Middle East.

The Doomsday Clock now stands at 89 seconds to midnight, the closest to catastrophe in its nearly eight-decade history. Here's a look at how — and why — it's moved.