Tear Jerker: Grave of the Fireflies
If you are looking for a tear jerker, look no further than "Grave of the Fireflies" (Original title: "Hotaru no haka") which tells the sale of a young boy of 14 and his 4 year old sister as they struggle to survive in Japan during World War II.
This movie is an older one, released in 1988 and based off a true story by Akiyuki Nosaka which chronicles his journey and loss due to the American fire bombing raids during WWII in his town of Kobe Japan.
Despite it being an older movie, the message conveyed is timeless, this is by far the darkest film released by the Studio Ghibli, a studio known for its anime feature films that are usually of a less sombre nature.
Though I don't want to give too many spoilers, at the beginning of the film we see the main character lying lifeless on the floor of a Tokyo subway while his ghost brings you on a journey through his memories.