Watership Down. Book is better, but the original film is profoundly moving.
Creation myths, how meaning is attached to life and natural phenomena, totalitarianism, mysticism, danger, loss, life, the will to survive, acceptance, environmentalism, the development of language, war, hope and the most tender, delicate and joyful depiction of death in literature.
'They went out past the young sentry, who paid the visitor no attention. The sun was shining and in spite of the cold there were a few bucks and does at silflay, keeping out of the wind as they nibbled the shoots of spring grass. It seemed to Hazel that he would not be needing his body anymore, so he left it lying on the edge of the ditch, but stopped for a moment to watch his rabbits and to try and get used to the extraordinary feeling that strength and speed were flowing inexhaustibly out of him into their sleek young bodies and healthy senses.
"You needn't worry about them," said his companion. "They'll be all right -- and thousands like them. If you'll come along, I'll show you what I mean."
He reached the top of the bank in a single, powerful leap. Hazel followed; and together they slipped away, running easily down through the wood, where the first primroses were beginning to bloom'