Inside Dargan Shelter, the Blue Mountains cave home to artefacts linked to the Ice Age (20,000 years) The terrain in the upper Blue Mountains is impassable in sections. It's where eucalypts climb high and scribbly gums, banksia and wattles thrive.

Survival in this environment today would be tough — which makes a recent archaeological discovery all the more extraordinary.

Scientists have uncovered Ice Age artefacts deep inside a cave 1,100 metres above sea level, challenging long-held assumptions about ancient human life in Australia.

The discoveries, dated to as far back as 20,000 years, were found in a cave known as Dargan Shelter — now believed to be the oldest known site of human activity at high elevation on the Australian continent. (read on)