World's oldest open caves near Sydney: scientists (Reuters)

SYDNEY (Reuters) - A series of limestone caves west of Sydney, best known as a popular family tourist attraction, are in fact the world's oldest open caves, dating back 340 million years, Australian scientists say. The Jenolan Caves in the Blue Mountains west of Sydney were thought to be only a few thousand years old but actually predate dinosaurs, said Armstrong Osborne, a member of a Sydney University scientific team which recently dated the caves. "We've shown that these caves are hundreds of ...