Mostly historians have assumed that populations that existed 8,000 years ago would be incapable of making such structures:

Now NASA has taken the first photos of the Steppe Geoglyphs from space, and has admitted that its scientists are no closer to solving the mystery. But they’re going to keep investigating, because the answer could reshape our understanding of early humanity.

“The idea that foragers could amass the numbers of people necessary to undertake large-scale projects – like creating the Kazakhstan geoglyphs – has caused archaeologists to deeply rethink the nature and timing of sophisticated large-scale human organisation as one that predates settled and civilised societies,” Persis B. Clarkson, an archaeologist at the University of Winnipeg, told Ralph Blumenthal from The New York Times.

These new pics are definitely making some historians rethink what they thought to be true about the people who inhabited that region.