Civilizations do not only progress; they can also regress.
Tasmania was connected to the Australian mainland, and ten thousand years ago, the sea level rose rapidly, turning Tasmania into an isolated small island, cut off from the world. Later, European whites set foot on this island, and they found that the indigenous people didn't even have the basic skill of making tools, such as simple weapons or tools by tying hard stones or animal bones to sticks to make spears, arrows, or axes. They didn't know how to!
It was even more primitive than the Old Stone Age!
Even though surrounded by seas and rich in fishery resources, they did not know how to fish.
They would not make clothes even in winter, and simply smeared animal fat on their bodies to keep warm.
The only skill they had was probably making fire!
