This is hard, because I think more than one can be a good answer for this question. I would say either Pocahontas, Beauty and the Beast or Snow White (yes, Snow White is actually pretty dark in my opinion!)

I wholeheartedly agree that Snow White is dark, the princess almost gets knifed in the woods and her stepmother wants her heart in a box!

And Pocahontas.

I think honor, pride, devotion, sense, sensibility, sense of justice, courage, affection, family, sense of sacrifice are very adult themes. Also Pocahontas, her story's about the differences of the human race and the love for the strangers. I also would say that The Little Mermaid speaks about the difference from the "normal" and the "strange", it's all about the prejudige about what's right and what's wrong. But this story, like Beauty and the Beast, couldn't be real, because of the mermaids or the Beast Adam, so I would pick at least Pocahontas. Cinderella speaks about envy and true love at first sight. Also Sleeping Beauty is about love and courage, Prince Philip is really brave. I think Princess and the Frog is about the sense of loss, the desire to rediscover our own priorities and the desire to rediscover our identity. And Rapunzel is the lost princess and her life is a very big deception. It's about the real friendship and the importance of the family love. So my answer is Mulan, but all of them have got adult themes.

Snow White... They have said it before me--^ I agree.

Or BatB.

& Mulan

Quite a bit of blood too!

Agree with everyone else Pocahontas and Mulan, they deal with war and violence and more realistic then the other ones that are obvious fairy tales.

Just Pocahontas IMO !

Could you make a countdown about this ?It would be great!

Pocahontas is defentaly the one with the adult theme because of the war,clashes of cultures,the romance,death,tragedy,and it's also the most dramatic then a fantasy.The other movie would be Mulan because of the war and so on.Also I think Tangled has some adult themes as well.It has Eugene getting stabbed by Gothel and him dying.Also there are some other themes to it too.

Also Mulan and Beauty and the Beast.

Definitely

Pocahontas definitely addresses certain messages that put this film into a category different from what you'd call a "kiddie movie" because it largely revolves around the adult themes such as racism and unacceptance, ability to let go of your prejudices and learning to look at things from a different angle changing your mindset and attitude regarding life and people, however, kids are often being taught by their own parents to be tolerant and accepting therefore I can't call the concept of the movie groundbreakingly "adult" for a family film. Tangled on the other hand starts with the themes and issues of bad parenting and emotional abuse from the get go represented through Rapunzel/Gothel relationship, showing the growth and recovery from Stocholm Syndrom and years of manipulation that the main protagonist had to endure for her entire life not to mention adding some clear mental and emotional instability to her characterization due to the way she was raised and oppressed. In addition to that the movie involves the theme of ultimate sacrifice ending with actual death (even if a not permanent one) of the other protagonist of the movie at some point.