Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is an experimental film from the great French director Louis Malle. At the beginning of the film we see a teenage girl named Lilly driving a car in a countryside where an army of men and an army of women are at war. She stops to watch a group of male soldiers execute a group of female soldiers, but she is spotted as a female and the men try to kill her. She escapes by driving her car off the road and deep into the woods where she finds an ancient road that is ultimately blocked by a fallen tree. She gets out of the car and begins lifting stones from the edge of the road so she can drive around the obstacle. Under one rock she finds a pair of snakes mating and she is startled and stops to stare blankly at them. As far as I can determine, they are Western Whip Snakes - Coluber viriflavidus, which are not native to southern France where the movie was filmed. (I like this reveal of the snakes because it involves rock flipping - an excellent herping technique.) The mating snakes watched by a young girl set us up for the adolescent journey into sexual awareness that follows, and a snake returns at the end of the film to help her, in a sybolic and creepy way that may be just the imaginings of the girl's psychotic mind. There are several scenes in the film where Lilly seems out of touch with physical reality which have been interpreted to mean that what we see on screen is derived from her psychotic visions.
But back to the snakes. As she is staring at them, she turns to see some female soldiers torturing a man. One of them spots her so she runs away wildly deeper into the woods. Eventually she gets to an old country house where she enters a strange surreal world with a talking unicorn that recites Shakespeare, with naked children who chase pigs, and where an old woman has conversations with a rat in a fantastic language. In the old woman's room Lilly opens a drawer and finds another snake. This one looks like some kind of North American gartersnake. And at the end of the film, another Western Whip Snake crawls up onto the bed where she is lying.