Walkabout (1971)

An adventure directed by Nicolas Roeg.
A father goes on a picnic with his daughter and son. The father begins shooting at his offspring, until he decides that they are going to avoid his shots. He then sets the car on fire and shoots himself. The older daughter salvages what she can from the picnic and the siblings run away, stranded in the Australian outback. They wander until they are on the brink of death, at which point they find an oasis that dries up overnight. They decide to stay there the following day, in hopes of the water returning. At this point, an aboriginal young man appears and becomes their guide. They can't help but follow him until they can find a way back to civilization.
Great film! It starts out tragic and disastrous, but turns into a psychedelic spiritual journey at some point. The camera goes wild in the outback, shooting whatever and showing short clips of the characters. Eventually things become coherent again as the native Australian is on a killing spree. He kills any animal in sight, and where they are, there are a lot of animals. Suddenly a jeep with shotgun hunters passes by and he sees them killing animals at about 1 animal per second. I saw jealousy in his eyes at this point, in awe of greater killing machines. He eventually goes insane and hangs himself in a tree after meditating among the bones of the dead in skeleton paint and scaring the sister by dancing provocatively, leaving the siblings on their own. At this point, a unique truck passes on the road. Now, I've heard of "18 wheelers" before, but never a "42 wheeler"! I have to rate this best. This is going into my collection.