A study reveals that the symbols were placed in accessible and visible areas for large groups, dismantling previous theories about their function.
The **El Castillo cave** , in Puente Viesgo (Cantabria, northern Spain), is one of the most important prehistoric sanctuaries in the world. On its walls, the men and women of the Upper Paleolithic left a record of their presence. But what exactly did they intend when they placed their hand on the rock and blew red pigment to leave their imprint forever? An international team of scientists has applied for the first time a combination of 3D technology, geographic information systems (GIS), and statistics to answer this question. And the conclusions, published in the journal _Archaeometry_ , change what we thought we knew.
The research, led by Olga Spaey (CNRS–University of Bordeaux), analyzed the 77 **negative hands** that dot the Cantabrian cavity. And it did so with a novel approach: instead of limiting themselves to looking at the walls, they virtually reconstructed the cave floor as it was more than 20,000 years ago, calculated the physical effort required to reach each symbol, and simulated the light of a torch to determine how many people could view them at the same time.
The results are, in some ways, surprising. _The hands were not hidden in inaccessible recesses nor did they mark dangerous areas_ , the study explains. _They are located in areas of easy access and could be seen by a large audience at the same time_. On average, each hand could be observed by 16 people simultaneously. In some points, such as the famous _**Ceiling of Hands**_ , the figure rises sharply: up to 31 individuals could contemplate most of the symbols without moving from their spot.
(A) View of the Gallery of the Discs where the discs accompany the visitor in direction of the last hand stencil of the cavity. (B) View of a hand stencil and discs together on the Ceiling of the Hands. (C1) View of the restricted passage, excavated in modern times. (C2) View of the 3D model with the recent anthropic changes highlighted in blue. (C3) View of the same area with the ground levels reconstructed on basis of historical archival documentation and geomorphological study. Credit: O. Spaey et al. 2025
To reach these figures, the team did not simply walk through the cave with a flashlight. They used high-precision 3D models and calculated the “difficulty of access” meter by meter. _We quantified the energetic cost of moving through the cave, combining two forms of locomotion: walking on flat areas and climbing on slopes_ , they explain in the article. Then, based on experimental studies of lighting in the Paleolithic, they simulated the reach of a wooden-torch flame (2.99 meters) and analyzed, from each stable point in the cavity, which hands were visible and how many people could fit to see them.
The analysis did not stop at the macroscale. The researchers also examined the exact position of each hand, the **posture that the artist had to adopt** to paint it, and the orientation of the fingers. And here another relevant finding emerged: the comfort of the performer was not the priority. What mattered was the chosen place on the wall. Thus, there are 12 hands made from a squatting or seated position, 19 slightly leaning, 30 between leaning and upright, 10 upright, and six for which the artist had to raise themselves above the ground.
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But if the objective was to be seen, **why are some hands so high or so low?** The answer, according to the authors, points to a **symbolic complexity** greater than previously thought. Most of the hands follow a natural pattern: the left hands are usually oriented toward the 10 and 2 positions on a clock (facing toward the center of the body of the person who made them), which suggests a relaxed and repetitive gesture. However, two examples break all the rules and offer fascinating clues.
(A) Situation of hand stencil 64 on the map of cave. (B) Rock-art survey of hand 64. (C) General picture of the area, where the situation of hand 64 is framed. (a) Detail of hand 64. (D) Orientation of all determinable hand stencils of the cave, with hand 64 emphasised. Credit: O. Spaey et al. 2025
The first is **hand number 64**. To paint it, the artist inserted their entire arm into a chimney-like crevice in the rock, an awkward and uncomfortable posture. The result is a hand that seems to emerge from the wall itself, as if coming out of another world. _Instead of the easiest position, Paleolithic people deliberately chose this uncomfortable placement, which could be the consequence of specific symbolic reasons_ , the research notes. The authors recall that some archaeologists have interpreted certain figures as **representations of the myth of primordial emergence** , according to which humans and animals came out of the earth through caves.
The second case is **hand number 9**. This one is located in a wide gallery, but hidden behind a thin panel of rock. Only 5.8 people could see it at the same time, the lowest figure in the entire cave. _It is a discreet hand in a public space_ , the scientists summarize. This duality has led the team to propose a more nuanced classification than the simple division between “public” and “private” spaces used in traditional archaeology.
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They now speak of _public spaces with prominent motifs_ (the majority) and _public spaces with discreet motifs_ (such as hand 9), in addition to restricted-access private spaces, which exist in El Castillo for other types of figures, but not for the hands.
## Paleolithic road signage?
One of the classic debates about negative hands is whether they functioned as topographic markers, that is, as **signals to guide visitors through the underground labyrinth**. The researchers’ answer is nuanced. On the one hand, they rule out that they served as a guiding system from the entrance: there are no hands at the beginning of the cave, and if a visitor followed the hands, they would miss most of them.
(A) Location of hand 9 on the cave map. (B) General image of the area, with the location of hand 9 highlighted. (C) Detail of the position of hand 9 on the 3D model. (D) Detail of the location of hand 9 on the textured three-dimensional model. (E) Photograph of hand 9. Credit: O. Spaey et al. 2025
However, when calculating the _least-cost path_ (the easiest route to traverse the cave), they discovered that practically all the hands are located along the main pathways. And above all, in the **Gallery of Hands** something exceptional occurs. This gallery narrows until it becomes a very tight passage. Well, the hands do not stop before that difficult passage; on the contrary, they continue on the other side. _The hypothesis of crossing the narrow section of the Gallery of Hands seems much more coherent_ , they state. If someone wanted to reach the hands at the end without passing through there, they would have to take a much longer and more complicated detour.
In addition, once the passage is crossed, a long row of **red discs** (painted dots) accompanies the visitor to the final hand, in the **Gallery of Discs**. The discs are made with the same technique and color as the hands and belong to the same period (Gravettian, between 33,000 and 25,000 years before present). For this reason, the authors propose a suggestive hypothesis: _The hands (and possibly also the discs) could be figures that mark important symbolic spaces and suggest links between the motifs, creating a graphic ensemble that, in order to be appreciated, requires traveling along a specific route_. In other words, they did not mark the entrance path, but they did **organize the internal route once one was already in the sacred area**.
One of the most innovative methodological aspects of the study is that it did not limit itself to analyzing the cave as it is today. The team, which includes geologists, reconstructed the Paleolithic landscape of El Castillo. And they verified that failing to do so leads to significant errors. For example, in the **Ceiling of Hands** , if the current floor is used (with modern stairs and uneven levels), it is estimated that 11 people could clearly see the panel. But with the reconstructed floor, the figure rises to 15, 30% more. _It implies that this method of analysis, which requires extensive preliminary work and critical thinking, yields results that could not be obtained with traditional methods_ , they conclude.
The study also took into account the possibility that the hands were not all contemporaneous. Although most are attributed to the **Gravettian** , if they were painted over several centuries, the later artists saw the earlier hands and decided to place theirs in relation to them, which gives coherence to the ensemble.
Finally, the scientists open the door to new social interpretations. The high visibility and the capacity to host large groups suggest that the creation or use of these symbols involved the community, not only isolated individuals. This fits with recent morphometric studies that identify hands of adults, but also of adolescents and children in the **Ceiling of Hands**.
_The data obtained invite us to consider the creation or use of these motifs by large groups_ , they conclude. And although the mystery of their ultimate meaning remains, we now know much more about how people related to them: they were not secret messages for a few initiates, but shared symbols, placed to be seen and, in some cases, to surprise the viewer by making a hand emerge from the rock or **pointing the way toward the deepest part of the mountain**.
The research will continue. The team plans to extend this same analysis to other caves with hands, such as Gargas, in France, to determine whether these spatial dynamics are repeated or whether each sanctuary had its own rules.
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**SOURCES**
**Spaey, O., I. Intxaurbe, I. Urrestarazu-Porta, et al**. 2026. _Mapping Palaeolithic Imprints: Spatial Analysis of Hand Stencils in El Castillo Cave (Spain) Through Geomatic Techniques_. Archaeometry 1–17. https://doi.org/10.1111/arcm.70120
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READ MORE ABOUTCantabria Paleolithic Parietal art Prehistoric Caves Rock Art Spain
