During the last glacial period, sea level was more than 100 metres below today's; Southeast Asia and Australia were a very different geography. Sunda — the enlarged Asian shelf — and Sahul — a single continent comprising Australia, New Guinea, and Tasmania — were two large landmasses. They were never connected by dry land: any crossing required at least seven or eight island-hopping legs, each one across tens of kilometres of open sea. The first humans to set out by boat toward a coast they could not see did this.

Excavations at the Madjedbebe rock shelter in northern Australia have recovered, in controlled stratigraphy, stone tools, grinding stones, and ochre remains dated to around 65,000 years ago. At Willandra Lakes in New South Wales, Mungo Man was deliberately buried with ochre about 42,000 years ago — a careful, ritualised burial. Together, the two finds show that humans did not stumble onto Sahul: the arriving population spread quickly, settled, and carried its symbolic world into the new landscape.

How the crossing was made is still debated — deliberate rafts? groups blown across by storms? What is certain is that, at least 65,000 years ago, humans were capable of reaching an unseen coast by boat. This stands as the distant precursor of the voyages that follow — from Polynesia's Pacific expansion to Columbus.