Anime of Despair

I am not into sad movies but, if you are, you should watch Grave of the Fireflies, a japanese anime about two war orphans.  It not only has a sad ending, but the anime starts with both of the orphans dead.  Just reading the storyline was enough for me to require tissues and a stiff drink.  I am a chicken when it comes to sad movies because they tend to crack me open like an oyster.