The Twelve Apostles, some of Australia's most recognisable landmarks, have been discovered in a new study by colleagues from the Australian Journal of Earth Sciences. The study, which involved mapping the cliffs and sea stacks using high-resolution digital imagery and analysing fossils of microscopic sea creatures trapped in the rock, revealed that each layer was laid down in shallow seas during the Miocene epoch. The oldest layers of limestone are about 14 million years old, and the youngest about 8.6 million years. The fossil analysis also revealed that the oldest layer of soft, dark material was deposited at the bottom of deeper, warmer seas around 14 million to 15 million years ago. This fossil record captures a moment when the global climate was warmer than today. The researchers are now working to reconstruct this in detail to reveal how climate levels and ocean conditions changed across millions of years of history.