The Bulletin of Atomic Scientists was founded in the US in 1945 to engage and educate scientists, policy makers and members of the public about nuclear weapons, disarmament, climate change and emerging technologies.
The Bulletin's famous doomsday clock, which is reassessed and reported on annually dependent on the level of nuclear threat, was first introduced in 1947, sitting at seven minutes to midnight.
Virtually all major news outlets have reported on the clock’s movements since its inception. Such is the story’s appeal, it currently sits in the top-ten most-read stories on the BBC, for example.
By 1953, the clock had moved to two minutes to midnight following the US' decision to pursue the hydrogen bomb. This was the closest to midnight the clock has been its 70-year history. From 1960 to 1980 the clock fluctuated from a position of 12 minutes to midnight (1963 & 1972) to a low of seven minutes to midnight in 1980.
After the cold war ended, more secure global relations followed, until 2010 when the clock sat at six minutes to midnight.
Since then, the doomsday clock has edged ever closer to midnight as nuclear weapons modernisations, unchecked climate change and increasing weapons arsenals have created an "extraordinary and undeniable threat to the continued existence of humanity", the Bulletin said.
In its latest doomsday report, the Bulletin said its decision to move the clock by 30 seconds - something it has never done before - reflects the fact that US President Donald Trump has broken with historical precedent in "unsettling ways".
"In short, even though he has just now taken office, the President's intemperate statements, lack of openness to expert advice, and questionable cabinet nominations have already made a bad international security situation worse."
Ominously, the Bulletin has warned: "It is two-and-a-half minutes to midnight, the clock is ticking, global danger looms... Wise public officials should act immediately, guiding humanity away from the brink. If they do not, wise citizens must step forward and lead the way."