A grim simulation reveals the horrifying mayhem that would ensue from a war between the US and Russia.
The ominous video shows how atomic bombs would rain down on Earth during the conflict, killing an estimated 34 million people in under five hours. Most would die within a 45-minute period, reports The Sun.
A further 60 million would be injured by the blasts, say experts at Princeton University in New Jersey.
They added that the number of fatalities would later skyrocket due to nuclear fallout and other long-term effects.
"This project is motivated by the need to highlight the potentially catastrophic consequences of current U.S. and Russian nuclear war plans," according to an official Princeton blog post.
"The risk of nuclear war has increased dramatically in the past two years as the United States and Russia have abandoned longstanding nuclear arms control treaties."
The four-minute simulation, titled "Plan A," depicts how a conflict between the United States and Russia could escalate from conventional war to an all-out nuclear conflict.
It's based on independent assessments of current U.S. and Russian force numbers, nuclear weapon targets, and fatality estimates.
War begins when Russia launches a nuclear warning shot from a base near the city of Kaliningrad in an attempt to halt a US-NATO advance across western Europe.
Fighting quickly escalates to a tactical nuclear war in Europe, with Russia and NATO forces exchanging 480 warheads via aircraft in an apocalyptic battle of the skies.
Casualties (meaning both deaths and injuries) hit 2.6 million within three hours.
With Europe destroyed, NATO fires 600 warheads from US land and submarine bases aimed at Russian nuclear forces.
Russia retaliates with missiles launched from silos and submarines. This exchange causes 3.4 million casualties within the next 45 minutes.
With the aim of blocking the other side's recovery, Russia and NATO each obliterate one another's 30 most populated cities using five to ten warheads on each town.
This leads to over 85.3 million casualties within the following 45 minutes.
"[The simulation] uses extensive data sets of the nuclear weapons currently deployed, weapon yields, and possible targets for particular weapons," reads the blog post.
It leads to around 91.5 million casualties across the entire conflict.
That includes 31.4 million fatalities and 57.4 million injuries.
"It shows the evolution of the nuclear conflict from tactical, to strategic to city-targeting phase."
While it may all sound a little far-fetched, the world is closer to nuclear war now than at any time since World War 2, according to one UN arms chief.
Renata Dwan, Director of the UN Institute for Disarmament Research, warned in May that all states with nuclear weapons are modernising them, increasing the threat of apocalypse.
She said it's important "to recognise that the risks of nuclear war are particularly high now, and the risks of the use of nuclear weapons, are higher now than at any time since World War Two."