"A goddamn mystery without a goddamn solution!" - Peter Weir quoting an American distributor who saw the film in 1975
It's very rare to see a film that walks on such a high tightrope as Picnic at Hanging Rock, and almost impossible to recall one that does it with such grace and commitment. Three girls and a schoolteacher disappear without a trace during a picnic in 1900, one of them to reappear a week later without any memory of what happened, the others never to return. No answers will ultimately be given, but the film is far from an exercise in pointless mystery, turning a sharp eye to the effects of the girls' disappearance on those left behind. It is, first and foremost, a story of how lives and relationships are destroyed by something utterly inexplicable and beyond the human comprehension, and the more time we spend with the characters, the more affecting it becomes.
There's certainly more than one way to see Hanging Rock: as a symbol of adult, sexual, free world that takes the girls away from their innocence while leaving the others confused and terrified in their repressive Victorian world; or, more easily, as a manifestation of some ancient forces that "wake up" and show themselves in a modern world to frightening, devastating consequences. Both interpretations are legit, and it's even possible to combine them into one, although the second one by itself is more attractive to lovers of genre film. And true, from a certain point of view, Picnic at Hanging Rock might be the most beautiful, elegant and tragic horror film ever made. But in the end, it survives as a classic largely because it so powerfully resists easy categorizing: a horror movie without a physical threat, a mystery without a solution, a film that's erotic without being sexy, hypnotic without being incomprehensible, and endlessly suggestive without being irritating or gimmicky. Pretty much flawless.