Need Help Finding An Animated Movie?

It was a long time ago when i saw this animated movie, about 5 or 6 years ago. so cannot recall much, the only scene I can remember is about a girl being discovered in the ruins by one or two people, probably small boys, and that's pretty early into the film. The setting of the film is some what like a industrialized city in the future but it's in ruins. So please help out if u can, just name anything that comes to ur mind :p thanks in advance~!!