When we visit an archaeological site, a monument or a cultural landscape, we are not looking for technology. We are looking to engage with the place itself: to understand what happened there, recognise traces of the past and connect with something that has survived to the present day. This principle is especially important for Augmented Reality (AR). Its value lies not in overlaying digital effects onto the physical world, but in providing information at the right time and in the right place, without overshadowing the heritage we seek to bring into focus.
Across various projects at the CCG/ZGDV Institute, we have been developing this idea at very different scales: from a rock art surface and an ancient Roman road to the cultural landscape seen from a train. RARAA, Geira — Via Romana XVIII and RAILtoLAND show that AR can offer far more than visual reconstruction. It can serve as a powerful lens for interpreting heritage.
When Technology Should Remain in the Background
One challenge of applying AR to heritage seems straightforward: to display digital information in the right place, the system needs to know its position and the direction the device is pointing. In controlled environments, markers, reference images or artificial features are commonly used to aid recognition. In heritage settings, this approach is not always desirable or even acceptable. Placing a marker on an archaeological surface simply to make an application work means, in a sense, adapting heritage to technology.
The approach we find more promising is the reverse: developing technology that can adapt to the place. This involves combining computer graphics, computer vision, three-dimensional models, spatial information and interaction design so that digital content can be accurately aligned with the physical world. Visitors should not have to search for an artificial symbol to begin the experience; ideally, the features of the heritage itself should underpin this relationship between the physical and the digital.
The aim shifts from placing a marker in the world for technology to recognise to enabling technology to recognise the place itself.
This approach reflects an international trend in using Augmented Reality in heritage settings. At rock art sites such as Cova dels Cavalls in Spain, the technology has been used to overlay motifs that are now difficult to discern directly onto the rock surface [1]; at monuments such as the Ara Pacis in Rome, the three-dimensional relief itself is recognised and tracked in real time to anchor digital content to the monument [2]; and, more recently, Pompeii has begun offering AR experiences that virtually recreate settings, furnishings and scenes of everyday life within the archaeological site itself [3]. These examples share a common aim: to use digital knowledge to make physical heritage easier to interpret, rather than to replace it.
RARAA: An Interpretative Lens on Rock 7
This challenge became particularly apparent in the RARAA project — Repositório de Arte Rupestre de Acesso Aberto (Open Access Rock Art Repository). An AR application was developed for Rock 7 at Vale de José Esteves in the Côa Valley, drawing on detailed scientific documentation: photogrammetric surveys and 3D models of the rock, orthophotos of the panels, drawings and descriptions of the engraved motifs. This digital foundation is therefore no decorative addition; it stems directly from archaeological documentation and interpretation.
The application was designed for two complementary settings. Indoors, the experience can use a representation of the panels, allowing users to explore the engravings away from their original location. This is relevant to museums, schools, interpretation centres, and other educational settings, as it broadens access to heritage that, because of its location and characteristics, is not physically accessible to everyone.
In situ, the challenge is more demanding and, at the same time, more interesting. Visitors stand before the actual rock, and the application must link digital content to the engraved panels without introducing artificial markers into the heritage setting. Alignment between the digital representation and the physical object becomes critical: if the motif shown on screen does not match the engraving on the surface, the technology stops helping and becomes a distraction.
When this alignment works, AR offers a particularly valuable capability for rock art. Many motifs are difficult for non-specialist visitors to identify: visibility may depend on lighting conditions, lines may be very faint, or motifs may overlap. The digital layer can selectively highlight a figure, a group of motifs, or a particular category, and provide associated interpretative information. Instead of looking at a separate illustration and trying to locate its subject on the rock, visitors can connect the interpretation directly with the surface in front of them.
This is where the idea of an “interpretative lens” comes into its own. AR does not replace observation of the rock: it guides it. It can temporarily make what is already there more visible and offer different levels of interpretation of the same heritage.
From the Surface to the Route and the Landscape
The same principle applies at other scales. In the Geira — Via Romana XVIII project, the experience extends beyond a single object to accompany visitors across an area. Between Roman miles XVII and XXXIV, in Terras de Bouro, the mobile application combines GPS navigation, multimedia content and Augmented Reality to help visitors discover the remains and landscape associated with the ancient Roman road. Here, the route becomes the interface: information appears when visitors reach the relevant place, helping connect scattered remains into a coherent spatial narrative.
With RAILtoLAND, the scale expands once again. The application was designed to enrich the Porto–Vigo rail journey by helping passengers discover the European cultural landscape along the route. Audio content, information on more than thirty points of interest, 3D models and AR features turn the journey into an opportunity for cultural discovery. The focus is no longer a single rock or an archaeological route followed on foot: the landscape itself, viewed on the move, becomes the interface with digital content.
Three scales, one shared idea: in RARAA, the surface is the interface; in Geira, the route is the interface; in RAILtoLAND, the landscape is the interface.
Augmenting Without Replacing
Immersive technologies are often associated with their ability to impress: three-dimensional reconstructions, animations, virtual characters or visually striking experiences. All these approaches can have value. In heritage settings, however, a more technically sophisticated experience is not necessarily better. The essential criterion should be how effectively it connects visitors with the place.
Technology should help us understand what no longer exists, identify what is difficult to see, provide context where explanation is needed and reveal spatial or temporal relationships that are not immediately apparent. It must also uphold scientific rigour, clearly distinguish data from interpretation and avoid presenting a hypothetical reconstruction as a visual certainty.
Accessibility is another important consideration. A digital experience can offer audio, captions, different levels of detail, multiple languages, interfaces tailored to different audiences or remote access to content that cannot be experienced in person. AR can therefore both enrich on-site visits and make heritage accessible to new audiences.
Generative AI could also support the creation, adaptation and updating of content — for example, at different levels of detail, in different formats or in multiple languages — provided that this content draws on validated heritage and scientific sources and is subject to specialist oversight.
The Next Step: More Natural, Persistent and Sustainable Experiences
Technological advances open up new possibilities. More robust visual positioning systems can progressively reduce reliance on markers; increasingly accurate 3D models can support research, conservation and communication alike; persistent spatial anchors can link content to a place more reliably; and data interoperability can allow a survey produced as part of a scientific project to be reused in educational, tourism or research applications.
Yet these advances also bring responsibility. An application created today must be designed to withstand rapid changes in devices, operating systems and platforms. In heritage, where timescales are necessarily long, digital sustainability is as important as innovation. Preserving models, metadata, interpretations and content in reusable formats is essential to ensure that knowledge is not lost when a technology is no longer supported.
Taking a Closer Look at What Is Already There
Digitising heritage does not mean replacing the experience of encountering it in person. Quite the opposite. AR’s greatest potential lies in using digital technology to encourage us to look more closely at the physical world. A good AR experience does not need to compete with an engraving thousands of years old, a Roman road or a cultural landscape. It should help us understand why they matter.
Another significant development is integrating intelligent avatars and conversational agents into heritage interpretation. In immersive or AR experiences, these virtual guides can engage visitors in conversation, answer questions, and adapt information to the context, their interests, or their location [4,5]. Beyond presenting predefined content, they could enable a more natural and personalised exploration of heritage, provided that their responses remain grounded in scientifically validated information.
When technology achieves this — when it ceases to be the centre of the experience and becomes a bridge between visitors, scientific knowledge and the place itself — augmenting reality no longer means adding elements to the world. It means enhancing our ability to understand it.
Opinion Article by:
Nuno Sousa, Researcher at CCG/ZGDV
Sources
[1] Blanco-Pons, S., Carrión-Ruiz, B., Lerma, J. L., & Villaverde, V. (2019). Design and implementation of an augmented reality application for rock art visualisation in Cova dels Cavalls (Spain). Journal of Cultural Heritage, 39, 177–185. https://doi.org/10.1016/j.culher.2019.03.014
[2] Museo dell’Ara Pacis. (2016–2019). L’Ara com’era – The Ara as it was. Roma Capitale / Sovrintendenza Capitolina ai Beni Culturali.
[3] Parco Archeologico di Pompei. (2026). Pompei lancia la realtà aumentata. La Casa del Citarista apre e diventa palestra per l’archeologia del futuro. Parco Archeologico di Pompei.
[4] Zhang, S., Ma, M., Li, Y., Man, K. L., Smith, J., & Yue, Y. (2025). The effects of LLM-empowered chatbots and avatar guides on the engagement, experience, and learning in virtual museums. International Journal of Human–Computer Interaction. https://doi.org/10.1080/10447318.2025.2494072
[5] Spallone, R., Lamberti, F., Olivieri, L. M., Ronco, F., & Lombardi, L. (2024). Augmented reality and avatars for museum heritage storytelling. In Beyond Digital Representation: Advanced Experiences in AR and AI for Cultural Heritage and Innovative Design (pp. 241–258). Springer. https://doi.org/10.1007/978-3-031-36155-5_16
