[Harmless Teddy Bear]

“Roundels were built during the Stone Age, when people had not yet discovered iron. The only tools they could use were made of stone and animal bones.”

Oh yikes.

Please let this be a translation error.

Because even I know that by 5000 BC people were using copper in Serbia.

[SunkenCiv]

The dates are one thing, the technology is another, IOW, stone (which is after all still in use) was supplanted by copper, on into bronze, and thereafter into iron, at different times in different places. For example, the bronze age in the Americas came along quite a long while after it was over elsewhere in the world.