20 ancient tools that archaeologists still can’t fully explain

Recovered from a shipwreck off the Greek island of Antikythera and dated to the 2nd or 1st century B.C., this bronze device used interlocking gears to track astronomical cycles. Researchers have made tremendous progress in studying it, although some missing parts, possible planetary displays, and the complete manufacturing process continue to raise questions.

Discovered in 1898 in a tomb at Saqqara, south of Cairo, this wooden bird, dating from around 200 B.C., continues to spark debate. Recent analyses have not confirmed its exact function, leaving it somewhere between a toy, a ritual object, and a model whose meaning has been lost.

This small pot, which is said to have been discovered near Khujut Rabu, contains a copper cylinder and an iron rod, which explains why it has been referred to for decades as an “ancient battery.” The problem is that the context of the discovery was poorly documented and the electrical hypothesis has still not been proven; the object therefore remains in a sort of archaeological limbo.

More than a hundred bronze dodecahedrons have been discovered in the northwestern part of the Roman Empire; they date from the 2nd to the 4th century CE. There is still no convincing consensus as to whether they were measuring instruments, ritual objects, knitting accessories, or something else entirely.

Byzantine forces used Greek fire beginning in the late 7th century, and the projection system often relied on siphons that propelled the flaming liquid outward. We know that this weapon existed and that it struck terror into the hearts of enemies, even though its exact formula and the workings of its pressurized system have yet to be fully elucidated.

These blades, dating from the Viking Age—approximately the 9th to the 11th century—were forged from steel of exceptional quality. Historians still debate today how this metal reached Northern Europe, what proportion came via trade routes linked to the Islamic world, and how many of the surviving examples are genuine originals rather than copies.

In the upper Semliki Valley, within the territory of what is now the Democratic Republic of the Congo, bone harpoons with barbed points dating back approximately 90,000 years attest to a very ancient fishing technology. Their general function is fairly clear, although the exact method of attachment, the fishing gear used, and the species most commonly targeted are still the subject of reconstructions based on scientific hypotheses.

At Pinnacle Point, on the southern coast of South Africa, more than 70,000 years ago, the inhabitants heat-treated chert to make it easier to flake. What remains a subject of debate is the exact pyrotechnic sequence, the degree of control over the heating process, and the extent to which this knowledge was actually widespread throughout the region.

About 13,000 years ago, toolmakers across North America produced fluted spear points, from which a long, channel-shaped strip had been removed from the base. Researchers are still debating whether the primary function of this groove was to improve the efficiency of the striking process, to absorb shock, or whether it served a more complex purpose.

Stone masons of the Egyptian Old Kingdom carved granite, basalt, and other hard stones with a precision that still sparks debate today. The real debate isn’t about imaginary machines. It’s about copper tools, abrasive sand, drilling methods, and the level of skill and repetition required to leave these clean saw and core-drilling marks.

On the Salisbury Plain in southern England, the massive sarsen boulders were shaped using mortise-and-tenon and tongue-and-groove joints—techniques more commonly associated with woodworking. What we still do not understand is that the process of cutting, lifting, and assembling these stones—which dates back to around 2500 B.C.—still leaves archaeologists with unanswered questions that they are eager to resolve.

Roman surgical kits discovered in Pompeii and Londinium, among other places, contain hooks, scalpels, probes, and forceps crafted with remarkable care. Researchers are still working to determine how specialized certain tools were, or to what extent these instrument kits were standardized.

These clay figurines from Japan’s Jōmon period, produced over a long period ending around the first millennium BCE, were not everyday objects, even though they were clearly part of a recurring human practice. The problem is that no one can say with certainty whether they are related to healing, fertility, protection, a ritual of destruction, or something a bit more mundane.

At Göbekli Tepe, in southeastern Turkey, communities living between 9600 and 8000 B.C. quarried, carved, and erected limestone pillars weighing several metric tons. Archaeologists have plausible theories regarding the work crews, quarrying, and transportation, although the exact logistical details remain somewhat unclear.

This famous embroidered cloak, which originated on the southern coast of Peru and is now generally associated with the Nasca tradition and dated to approximately 100–300 CE, represents a true technical feat in the art of weaving. Researchers have gained a thorough understanding of its sewing techniques and color work, although not all details—such as images, working conditions in the workshops, or production stages—have yet been clearly established.

About 200,000 years ago, Neanderthals in Europe were making birch tar to use as an adhesive. Experimental archaeology has revealed several possible methods, although researchers are still debating the complexity of the original process and wondering whether it required more preparation than previously thought.

Acheulean hand axes spread throughout Africa and then into Eurasia, and many of them were crafted with a symmetry that still catches the eye today. While their practical utility is beyond doubt, archaeologists still wonder why certain artisans devoted so much effort to their final form, and whether this symmetry served a social or religious function in addition to its practical purpose.

The Levallois technique is found throughout prehistoric Africa and Europe; it involved shaping a stone core so that a single strike would produce a flake of a controlled shape. It marks a major technical turning point, although researchers continue to debate how this technique spread, whether it arose independently on multiple occasions, and the extent to which direct instruction played a role in its acquisition.

Ancient Chinese texts describe a chariot whose needle remained pointed southward no matter how it turned, generally thanks to a gear system that later authors have associated with a primitive differential mechanism. The problem is that no original examples have survived; therefore, every reconstruction must rely on these texts and the technical knowledge of the time.

Electrum coins from Western Anatolia first appeared during the 7th and 6th centuries BCE. They are often regarded as marking the beginning of true currency. While their historical significance is clear, historians continue to debate how quickly standardization took place, how these coins came to be accepted as a medium of exchange, and what problem they actually solved.