Until the early 1990s, most residents of France's Aveyron valley were unaware of the Bruniquel cave. It needed a teenage boy to spend three years clearing rubble to open it.

When the members of the local caving club who were thin enough explored it, they came to a large chamber. They found several stalagmitesThese grow upwards when water drips onto cave floors. Stalactites, by contrast, grow downwards when water drips through cave ceilings. which had been arranged into rings and mounds.

An archaeologist estimated they were 47,600 years old - older than any known cave painting. But now, experts have revealed they are around 176,500 years.

At 176,500 years old, the arrangements are tens of thousands of years older than any known structure built by humans.

Today, the archaeologists understand the arrangements were not constructed by homo sapiensThe species to which all modern humans belong. Homo sapiens means "wise man" in Latin. . They were made by an entirely different species: NeanderthalsAn extinct hominid species that lived alongside Homo sapiens until around 40,000 years ago. Their ancestry began in Africa, like ours, but neanderthals migrated to Europe and Asia long before humans. They looked like us but were shorter and stockier with angled cheekbones, prominent brows and wide noses. . 

Neanderthals are modern humans' closest extinct relatives. They often took shelter from ice age weather in caves, before dying out approximately 40,000 years ago. Their name conjures up images of unintelligent brutesViolently savage people.. But their reputation has been revised.

Scientists have refuted the notion that they died out because they lacked intelligence. We now know they used fire, made tools, created art, looked after the sick and buried their dead. And the Bruniquel cave find suggests they were builders who worked cooperatively and may have observed social rituals.

Humans have long thought their cognitive powers make them unique. Many believe that "the difference between humans and other animals is fundamental, rather than one of degree", declares author Dr Helene Guldberg. 

Those views have been challenged. Darwin's discovery of evolution made clear that man was related to other animals. And some evidence suggests that dogs have picked up human traits and rats cooperate in sophisticated ways.

Now it seems our closest cousins were more intelligent than we realised. Neanderthals may have had prominent brows and weak chins like their early ancestors, but their brains were as big as modern humans'. 

Whereas scientists once thought modern humans had very little contact with other humans, some now theorise Neanderthals actually taught homo sapiens key skills. 

For some, it is proof: humankind must fundamentally rethink our understanding of ourselves and our place in the world.

Yes: Other creatures live to survive whereas we are moral, emotional beings, capable of calculated acts of good and evil. Our superior social skills and natural urges to cooperate are clear from a young age.

No: The more we investigate, the more we find similarities between animals and humans. Chimps use tools, laugh and adopt facial expressions and understand fairness, empathy and altruismA devotion to or selfless care for others.. 

Or... Neanderthals were not the brutes we once thought. But humans are much more sophisticated than our closest living relatives, chimpanzees. In today's world, we are unique. 

Stalagmites - These grow upwards when water drips onto cave floors. Stalactites, by contrast, grow downwards when water drips through cave ceilings.

Homo sapiens - The species to which all modern humans belong. Homo sapiens means "wise man" in Latin.

Neanderthals - An extinct hominid species that lived alongside Homo sapiens until around 40,000 years ago. Their ancestry began in Africa, like ours, but neanderthals migrated to Europe and Asia long before humans. They looked like us but were shorter and stockier with angled cheekbones, prominent brows and wide noses.

Brutes - Violently savage people.

Altruism - A devotion to or selfless care for others.