28 ancient humans dumped into a cave shaft 430,000 years ago. Possibly the earliest evidence of deliberate disposal of the dead.
Dorieo, CC BY-SA 4.0, via Wikimedia Commons
A Middle Pleistocene Cold Case
Deep inside the Cueva Mayor cave system in Spain's Atapuerca Mountains lies a chamber called Sima de los Huesos, the "Pit of Bones." It sits at the bottom of a vertical, 13-meter (43-foot) shaft. In this one small chamber, paleoanthropologists have unearthed more than 7,000 human fossils, dated to 430,000 years ago. These fossils represent the remains of at least 28 different individuals, making it the largest collection of Middle Pleistocene human fossils ever found at a single site. The individuals are classified as early Neanderthals or their direct ancestors, Homo heidelbergensis.
The sheer concentration of bodies in such an inaccessible location presents a puzzle. The bones belong to adolescents and young adults; there are very few children or older individuals. This demographic profile is not typical of a natural catastrophe. The study of the site's formation, or taphonomy, largely rules out accumulation by carnivores or geological forces like a mudflow. The bodies appear to have been dropped down the shaft intact and at around the same time. This evidence shows the intentional disposal of corpses by other humans, a behavior previously thought to have emerged much later in human evolution.
A Murder and a Ritual
Forensic analysis of the skulls has revealed a violent story. One specimen, Cranium 17, shows two almost identical holes just above the left eye. The shape and trajectory of the fractures indicate they were caused by two separate, face-to-face blows with the same object. The injuries show no signs of healing, meaning they occurred at or near the time of death and were likely the fatal event. This skull is considered the earliest known evidence of lethal interpersonal violence, or murder, in the human fossil record. The individual was already dead before being cast into the pit.
Adding to the mystery is the discovery of a single, masterfully crafted stone tool among the thousands of bones. Nicknamed "Excalibur," it is a hand axe made of a reddish quartzite, a type of stone not found in the immediate area. No other tools or animal butchery marks were found, suggesting the Sima was not a living space. The presence of this unique object has led researchers to propose that it was a symbolic offering. The deliberate placement of a special item with the dead implies a ritualistic or funerary behavior. Together, the evidence from the Sima de los Huesos suggests that 430,000 years ago, early humans were killing each other and engaging in complex, symbolic practices for disposing of their dead.
💡Fun Facts
The name "Sima de los Huesos" is Spanish for "Pit of the Bones."
Scientists successfully extracted nuclear DNA from the 430,000-year-old fossils, pushing the known limits of ancient DNA survival.
The remains found here represent about 80% of all known Middle Pleistocene human fossils in the world.
The hand axe "Excalibur" is made from a type of reddish quartzite that, when wet, takes on the color of fresh blood.
The Sima de los Huesos pit is an active research site and is not open to the public. However, you can visit the nearby Museum of Human Evolution in Burgos, which houses the main fossils. Museum hours are typically Tuesday-Friday 10:00-14:30 and 16:30-20:00, Saturday 10:00-20:00, and Sunday 10:00-15:00. It is closed on Mondays.
Admission
General admission for the Museum of Human Evolution is around €6. Entry is free on Wednesdays and on Tuesdays and Thursdays after 19:00. Guided tours of the Atapuerca archaeological sites (which do not enter the Sima pit) must be booked in advance and require a bus transfer from a visitor center.
Accessibility
The Museum of Human Evolution in Burgos is a modern facility and is wheelchair accessible. The external archaeological sites involve walking on unpaved paths.
