Casarabe is the name of a village with just over 900 inhabitants in north-eastern Bolivia.
Here you are far beyond the Andes, where the high culture of Tiwanaku once flourished or the Inca Empire.
The area is deep in the Amazon Basin, which up until about 20 years ago, at most, a few gold-hungry adventurers believed was ever inhabited in pre-Hispanic times by anything other than a few isolated tribes in tiny settlement sites, each consisting of at most a few huts passed.
But now Casarabe is naming an archaeological culture that thrived between AD 500 and 1400 on the Mojos Plain in what is now the Bolivian province of Beni - and which now turns out to have been a veritable urban civilization.
Ulf von Rauchhaupt
Editor in the “Science” section of the Frankfurter Allgemeine Sunday newspaper.
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At least that is what new data suggests, which Heiko Prümers from the Bonn-based Commission for Archeology of Non-European Cultures of the German Archaeological Institute and his colleagues published last week in "Nature".
Prümers has been digging in the Llanos de Mojos for more than twenty years and has therefore already come across sufficient evidence that this area was already being used extensively for agriculture in pre-Hispanic times - contrary to older doctrines that the soils there were too bad for such things.
The Casarabe were also known to have built several large structures and hundreds of kilometers of causeways and water channels.
But only a modern aerial archeological technique called "Lidar" - a kind of radar with laser beams instead of radio waves - now brings the manifest urban dimension of the Casarabe culture to light: It showed up as Prümers and colleagues from the lidar data they 2019 recorded during helicopter flights, had a computer calculate the signals from the trees and bushes.
As a result, under the vegetation of the savannah landscape and the gallery forests running through it, not only 24 smaller settlement structures came to light, of which only 15 had previously been known, but also two almost enormous centers of a hierarchically structured system of settlements of different sizes, which were of a complex and probable no less hierarchical society.
They are all earthworks.
"Stones are completely missing in the region," says Prümers.
Until the end of the 19th century, stones were even sold on the market in the provincial capital to sharpen knives, for example.
But the lords of these stoneless cities ruled over a community that knew how to tame the water of the rivers that burst their banks every year with causeways and extensive canal systems.
Last but not least, the sophisticated water management is reminiscent of the Maya in Central America, where a lowland that was actually unsuitable for intensive agriculture also produced a populous high culture and fed it for two thousand years.
However, while the Maya were demonstrably in contact with their neighboring high cultures further west in present-day Mexico, the question of the relationship between the Casarabe and the Tiwanaku culture, for example, which existed at the same time, is still in its infancy.
"The layout of the settlements is very different from what we know from the Andes," says Heiko Prümers about the buildings of the Casarabe.
"It's useful in that it severely curtails the otherwise certain discussion about whether the settlements aren't a highland takeover."
The fact that the Casarabe erected U-shaped platform buildings is somewhat disturbing.
“They are known from the Andes region right from the beginning of the first cultic interpretations.
They were not previously known from the Amazon region – but very little is known from there at all.”
In fact, evidence of complex agrarian communities has also been found elsewhere in the Amazon, some more than a thousand kilometers to the east, on the upper reaches of the Xingu River in the Brazilian state of Mato Grosso.
But the label of urbanity can be questioned far more there than with the Casarabe, whose largest legacies discovered by lidar can hardly be interpreted as anything other than ceremonial centers, especially since the buildings show a systematic north-northwest orientation, which can also be seen in the burials who found Casarabe.
However, it remains unclear why the Casarabe culture perished.
The Spaniards and the pathogens they brought in only came 200 years after their demise, and the Incas, who were also quite willing to conquer, probably never advanced to this area.
"There are many possible scenarios for the end of the Casarabe culture," says Heiko Prümers.
“A prolonged period of drought, disease, war – generations of archaeologists have been arguing about the end of the Maya culture.
I leave that to the next generation for Casarabe culture.”
One might look at the extensive defenses revealed in the lidar images as clues that the tropics may be engulfed in wars.
But for Heiko Prümers that would be a hasty conclusion.
"The defensive structures are of course very noticeable," he says.
"You don't build something like that without a reason.
It is therefore surprising that we did not find any traces of 'interpersonal violence' during our excavations.
But maybe the warriors were buried separately.” Many different explanations are possible here.
“The dense network of paths and canals that connects the settlements is actually an expression of strong social cohesion.
But maybe there was a Putin there too from time to time.”