I cried several times during this movie, which I watched recently on YouTube.
Deep in My Heart (1999)
A white woman who was raped by a black man gives the baby up for adoption. The film follows the life of the child as she grows up and has children of her own.
The rape takes place in the 1950s. The white woman is Catholic and doesn’t consider abortion, though it wasn’t legal then anyway. She doesn’t keep the baby because she thinks it would have a better chance at life with a black family. The child stays in foster care until she is about eight, when, in the early 60s, she is adopted, ironically, by a white family.
My answer was taken in the OP, but in an attempt to add to this thread I’ll mention part of a film.
There’s an Italian parody of Disney’s Fantasia called Allegro non Troppo, featuring animated segments set to classical music with some live action scenes as a framing device. One of the music segments is set to Sibelius’ “Valse Triste” and features a cat wandering through the ruins of a old house, remembering happy times in the past. If you ever want to see me as a soggy sobbing wreck, make me watch this because it gets me every time.
I recommend the whole film, actually - it’s 1970’s-style Italian dark satire but for all that it’s worth watching.
In the scene after the boy dies when all of those cars drive up to the house, hundreds of cars headlights in the dark. Coming to tell the mother how much her boy meant to them.
Near the end "Amazing Grace " is played on the flute. I haven’t seen the movie in more than 40 years but that tune is one of the very small number of things that can get me weepy. And all because of this movie.
I see Schindler’s List appear on a lot of people’s choices and while I agree, the subject and scenes are horrific and sad, the ending, showing all of the descendants that are alive today because of the list gives a somewhat upbeat and “happy” result. (I know it’s not happy, but I think you see what I’m trying to say.
For a really sad ending for a film that also deals with the horrors of the holocaust, I dare anyone to watch the film The Boy In The Striped Pajamas and not have your heart ripped out by the end of the movie.
My top ‘saddest ever’ is Grave of the Fireflies, same as so many others here.
But two TV bits can always make me cry.
One is Lonesome Dove. It’s overall a rollicking adventure, but the miniseries format lets you get to know the characters well, so it hit me hard when Augustus McCrae died. I think especially because he went slowly, and was more pissed off that he was dying when there were still things left to enjoy.
The other one that always gets me, believe it or not, is Garfield: His Nine Lives. Specifically: his (her?) sixth life, when Sara (her owner) realizes Diana is dying and plays an entire piano concert just for her, and then Diana steps down onto the keyboard and dies quietly during the night.
I saw it in the theater, and during the scene referred to in the title, there were loud, gut-wrenching sobs all over the theater.
Someone else mentioned Avalon. I cried all the way home from that one at the way TV ruined the close, connected family life of the characters. A destruction that smartphones and social media have pretty much completed.
I have to watch movies at home b/c I need to have CC but if I had been at the theater I would had let out a gut-wrenching sob too , I did while watching this at home. One of my BIL said he would never watch it again .
“It’s such a beautiful day.” The final film is a combination of three separate shorts: “Everything will be OK” “I’m so proud of you” and “It’s such a beautiful day.” Hands-down the most life-changing stick figure animation out there. After watching it, I walked around in a daze for about a week. It wasn’t sad exactly - not the kind of thing that makes people cry - just horribly, beautifully depressing, followed by this moment at the end where - well, no spoilers.