Hi, Picnic at Hanging Rock by Joan Lindsay is considered to be Australia’s most famous novel.There was also a film made. Here's a summary:
In 1900, a class of young women from an exclusive private school go on an excursion to the isolated Hanging Rock, deep in the Australian bush. The excursion ends in tragedy when three girls and a teacher mysteriously vanish after climbing the rock. Only one girl returns, with no memory of what has become of the others .