"It is protected by two strings of mountains, it is rich in fauna, it is a privileged spot from an environmental viewpoint, and it is ideal for the Neanderthal, given that it provided the with good hunting grounds."

This is not just a hypothesis: scientists working on site in Pinilla del Valle, near the reservoir, have already found nine Neanderthal teeth, remains of bonfires and thousands of animal fossils, including some from enormous aurochs (the ancestor of cattle, each the length of two bulls), rhinoceros and fallow deer.

The Neanderthal is a human species that is well known and unknown at the same time. It is well known because numerous vestiges have been found from the time when they lived in Europe, between 200,000 and 30,000 years ago. But it is also unknown because of the many unresolved issues that keep cropping up, including, first and foremost: why did they become extinct just as our current species made an appearance on the continent?

Nobody knows for sure whether the Neanderthal was able to talk, or whether they shared territory with Homo sapiens, or whether both species ignored each other until one - ours - proliferated while the other got lost forever... Scientists in charge of the sites at Pinilla del Valle could make significant contributions to finding the answers to these and other questions about the lives of the Neanderthal people.

"There are around 15 sites in Spain: in the Cantabrian mountain range, along the eastern Mediterranean coast and in Andalusia, but none on the plateau, where there are no limestone formations and no adequate caves to preserve human remains for thousands of years," adds Arsuaga. But Pinilla del Valle is an exception to the rule. "There is limestone here. It was like a cap made of stone under which the Neanderthal presumably took refuge to prepare for the hunt, to craft their tools, to eat... It's not that they lived inside in the sense of a home; they wandered in the fields, and this was probably more like a base camp to take refuge when they needed to."