(Warriors of the Wind)
Manga: 1982
Anime: 1984
Kaze no Tani no Nausicaa is set in the future, after a holocaust has devastated the earth. Humans live at a low technological level in a world on the edge of poisonous jungles filled with mutated animals. Although some machines remain from before the holocaust, most of them are clearly falling apart and, without any new technology, humanity seems to be slipping back into a fairly primitive lifestyle. Nausicaa (Zandra), the main character, is a princess in the Valley of the Winds. She finds herself involved in war, as certain groups attempt to revive old technology they don't really understand and threaten to destroy the earth again.
Nausicaa was popular when it first appeared as a serial in the magazine Animage, but was much more popular as an animated film. In fact it is definitely one of the most, if not the most, popular animated movie ever. It has been translated into English as Warriors of the Wind, but the translation is terrible, the editing worse, and the final result an embarassment to the original.
Personally, I thought the movie was quite a success in its English version. But perhaps I am biased; I grew up watching the movie, and probably could not tell the difference between what was good and bad film-wise. Now it's more of a cherished childhood memory, of which I can see no flaws. You'll have to watch it and decide for yourself.
Most info found at http://ucsu.colorado.edu/