In 1921, a miner’s dynamite blast in Zambia unearthed a face that rewrote the map of human evolution

The quest for our origins seems like an organised expedition at first glance, but some of the most spine-chilling parts of the human puzzle have emerged in a cloud of dust and dirt. In 1921, during the summer, miners working in a lead and zinc mine of Broken Hill, now known as Kabwe in Zambia, began excavating the limestone hills through blasting. The cloud of dust gradually cleared to reveal a human-like face gazing back at one of the miners, named Tom Zwiglaar, who worked there. He had discovered what would turn out to be an almost complete skull with prominent features.

This particular specimen is today recognised as the Broken Hill skull or Kabwe 1 and is considered to be the very first early human fossil found in Africa. In the context of the time when the fossil was discovered, it came as a shock since there were still many who believed that the origins of humanity should be searched for somewhere else. In the case of this fossil, people saw a brain that had reached the size of contemporary humans while featuring huge shelf-like brow ridges that were more pronounced than in any other fossil found.

A fossil that does not want to fit into the drawer

There was no doubt that the discovery caused a huge stir among researchers; at the same time, it posed serious taxonomic questions which have remained unanswered to date. While considering what species Kabwe 1 belonged to, early researchers could not decide whether this was the direct ancestor or rather one of the cousins that went extinct long ago. In accordance with information available at the Smithsonian Institution, Kabwe 1 was classified as a representative of a new species named Homo rhodesiensis. Later on, it was included in Homo heidelbergensis.

It is precisely this ambiguity that makes the Broken Hill skull such an important artefact for our time because it marks a point in Africa's history during which there could have been a variety of human races, evolving alongside each other and possibly even interbreeding. Rather than drawing a clear path from "ape-like" creatures to "modern-day" humans, the skull shows that evolution can take a number of experimental turns; some lead nowhere and end quietly in a limestone cave, while others thrive and continue the process.

New dating for an old ancestor

The date of the fossil had remained a mystery for several decades because the cave in which it was discovered was mined before scientists could examine it. However, the latest advances in technology have provided scientists with new insight into the Broken Hill skull. In the study published in the Nature journal, the skull and sediments associated with it were analysed using uranium series dating, and it was revealed that it is considerably younger than was believed before.

All of a sudden, the timeline has been updated, making a completely different picture appear. According to what was discovered as per the National History Museum, during the time the robust and primitive human was moving around in Zambia, the first representatives of our species, Homo sapiens, emerged somewhere else on the territory of Africa. Consequently, the idea that evolution is a race of some sort during which one type of human replaces another one becomes untrue. The reality is more complicated – it consists of various kinds of humans living in Africa at the same time.

The 1921 mining disaster is a great case in point to prove that accidental discoveries are helpful in developing a certain notion of oneself. Indeed, while Tom Zwiglaar was searching for the zinc ore, he stumbled upon something far more interesting. In this case, his accidental discovery led to a better understanding of the past of our ancestors. The Broken Hill skull can now be seen in the Natural History Museum of London, and its existence encourages scientists to rethink their theories on prehistory.

One wonders how many thousands of years ago there were people so radically different from what we think of as a human being that they might seem right out of a fantasy novel rather than a science textbook.