Poll Suggestion: Devastating Ending

@HamidrezaMpmm ,

For your consideration (FYC):

Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964)

https://www.imdb.com/title/tt0057012/plotsummary/

... As they start their bomb run, the damaged B-52's bomb bay doors will not open, and aircraft commander Major T. J. "King" Kong (Slim Pickens) goes down to the bomb bay to open them himself. He succeeds just as the plane reaches its target, and one of the nuclear bombs falls, with Kong still sitting on it. He straddles the bomb and rides it to the ground like a rodeo cowboy, whooping and hollering and waving his cowboy hat. The bomb explodes, triggering the Doomsday Machine.

... A visibly excited Dr. Strangelove bolts out of his wheelchair, shouting "Mein Führer, I can walk!". Abruptly, the film ends with a barrage of nuclear explosions, accompanied by Vera Lynn's famous World War II song "We'll Meet Again".

Fail Safe (1964)

https://www.imdb.com/title/tt0058083/plotsummary/

Making matters worse, when The President innocently asks the Soviet Premier about jamming of Group Six's radios, the Russian initially lies about it, and when he finally tells the truth the President still cannot convince Group Six to disengage. A direct communication link to Soviet air defense headquarters is opened and General Bogan is forced to dragoon one of his technical sergeants into telling the Russians how to detonate nuclear-armed air-to-air missiles, thus blowing up their own planes.

With all indications being that the bombers will reach Moscow, the President makes a deal with the Soviets - a deal so stunning as to shake even the Soviet Premier into realizing that the President's pleas that the attack is an accident are manifestly the truth, but with the sickening realization that the President's proposal is the only way to avoid omnicide.

omnicide - noun:  The total extinction of the human species as a result of human action. Most commonly it refers to human extinction through nuclear warfare, but it can also refer to such extinction through other means such as global anthropogenic ecological catastrophe.

On the Beach (1959) 

https://www.imdb.com/title/tt0053137/plotsummary/

... The final scenes take place days later, after the last remaining pockets of humanity have died. They show an empty, wind-blown and desolate Melbourne, before the movie ends with a rise of dramatic, strident music over the powerful image of a close-up of a banner seen previously at a Salvation Army gathering in the city centre only days before. The banner prophetically reads "There is still time...Brother".

My opinion is The Mist 2007 . Stephen King is a master of such stories, but in the book, everything ends ambiguously. The ending of this movie, however, can simply crush you. I don't want to spoil it, just in case someone hasn't watched it, which is unlikely, but if you are empathetic enough, it's a very devastating turn of events.