South Uist, in the Outer Hebrides, is home to hundreds of archaeological sites spanning thousands of years of occupation. Despite this rich heritage, incredible preservation conditions, and decades of illuminating archaeological research, there is very little for people to see on the ground. As a result, wider public awareness of, and engagement with, the island’s unique prehistoric and early historic-period heritage is not what it could be. This is something that the Uist Unearthed project has set out to address by reimagining some of these archaeological sites using cutting-edge augmented reality (AR) and virtual reality (VR) technology. The result has been a new app and an exhibition – but how did these come about?
An island rich in archaeology
People have been living in South Uist for millennia, leaving behind them archaeological sites of local, national, and international significance. It should come as no surprise, then, that there has also been a long history of excavation and research on the island, most notably the SEARCH project: a collaboration between Cardiff University and the University of Sheffield that ran between 1988 and 2002. This research initiative included excavation of some of Scotland’s most significant prehistoric and early historic-period sites. The Bronze Age settlement at Cladh Hallan, for example, revealed evidence for complex burial practices hitherto unknown and unidentified elsewhere in Europe (see CA 382). A few miles up the beach, geophysical survey helped the team identify one of Scotland’s largest Viking trading sites at Bornais.
We have the machair – a series of environmental zones on the island’s west side, formed from windblown, calcareous (marine shell) sand – to thank for the excellent survival of archaeological remains in South Uist (its high pH value greatly aids bone preservation, too). The dynamic nature of this shifting landscape has seen features – including entire settlements – being covered for centuries, protecting deeply stratified deposits. This environment became an important part of the settled landscape at the beginning of the Bronze Age approximately 4,000 years ago, and for much of prehistory the machair was a desirable place to live – a busy, bustling landscape, alive with the sound of birdsong, people, and animals.
This was certainly the case during the Iron Age, when wheelhouses like the one found at Cill Donnain were dotted along Uist’s west coast. Meanwhile, archaeological evidence from sites like the Viking longhouse at Bornais indicate that the machair remained hugely important into the early historic period and beyond. This ‘busy’ view of the past is at odds with our modern perception of South Uist, especially from a visitor perspective, which often focuses on the island’s perceived remoteness. For much of the past, however, the island was far from peripheral, but rather a well-connected place.
Archaeological research across the island has shed vivid light on prehistoric and historic settlement patterns, and the SEARCH project in particular has also included groundbreaking analysis of human and faunal remains that has helped to refine fieldwork techniques. But despite decades of top-quality research on the island, South Uist’s archaeological heritage has been poorly presented and communicated to the wider public. There is very little to see on the ground, limited signage, and a resulting lack of awareness of the island’s significance in the prehistoric and early historic periods. Cladh Hallan and the wider Daliburgh machair, for example, is a popular spot for local dog walkers, yet many residents are unaware of the importance of the archaeology lying beneath their feet. Visitors have limited awareness of the site, too – and are occasionally even seen setting up their tents within the shallow bowls that represent the footprints of Bronze Age roundhouses.
There are reasons and explanations for the lack of infrastructure and wider engagement. First, Uist’s archaeological remains themselves are challenging for visitors – we lack the dramatic and impressive upstanding remains that most people associate with Scottish island archaeology (think of Callanish in Lewis or Skara Brae in Orkney). Instead, most of our archaeological sites remain buried within the machair with very little to see and engage with ‘on the ground’. Some of our other significant sites are located in relatively inaccessible areas of the landscape: in remote parts of the moorland and on small islets within extensive loch systems. Additionally, only a handful of sites are furnished with any form of interpretation, and there is minimal signposting. A further challenge is presented by the fragile landscapes in which these archaeological sites are located, which can hamper efforts to develop access and associated visitor interpretation and facilities.
What South Uist does have, however, are rich archaeological landscapes with wonderful stories to tell. In order to address these challenges and make the most of these opportunities, we have created Uist Unearthed: a free, cross-platform mobile app containing digital reconstructions of three key archaeological sites located along the Hebridean Way walking route on the island.
The app presents users with stunning, life-sized digital reconstructions of sites as they might have looked, using augmented reality (AR). This technology allows digital information (such as text, images, 3D models, or audio) to be projected over your normal scope of vision, enhancing it with new details. Through the app, long-vanished settlements spring to life once more, enabling visitors to experience these sites in a new light. Uist Unearthed uses location-triggered technology and AR alignments, alongside animation, photography, 3D models, and audio, to create a truly unique offering in the heritage interpretation field.
Like most archaeologists, we argue that archaeological sites are best understood within their landscape context – and a key aim of ours has been to encourage people to get out and about in South Uist’s diverse landscapes and explore the sites directly. As a result, the full AR reconstructions of settlements as they may have looked in their heyday can only be accessed at the sites themselves – but if you can’t make it to Uist you can still download the app to learn more remotely from its text, infographics, and stories. There are also opportunities to visit our travelling Uist Unearthed multimedia exhibition, which reuses content from the app in new and exciting ways, such as VR headsets and 3D printed objects.
Cladh Hallan is the site of an impressive Bronze Age settlement. The earliest known evidence for activity at this location is a series of plough-marks in the sand that date to about 2000 BC. The first roundhouses were built there around 1100 BC, and the site was finally abandoned during the Iron Age, around 700 BC.
Cladh Hallan was excavated by archaeologists from the University of Sheffield between 1989 and 2003. The well-preserved roundhouse floors meant that the excavators were able to identify where certain activities had taken place. Crafting and cooking took place in the south, while sleeping and ritual activities took place in the north. Enigmatic ‘mummified’ human remains were found buried under the roundhouse floors, as well as many other unusual artefacts. Intriguingly, both ‘mummies’ were composites made from the preserved remains of several individuals who had died between 300 and 400 years earlier. They were the first prehistoric ‘mummies’ discovered in Western Europe, and analysis of the bones showed traces of acid damage. This is an important clue as it suggests that they had probably been buried in a peat bog away from the site to aid preservation, and then recovered before the bones could dissolve. This discovery laid the groundwork for a new technique that has since identified more evidence for mummification across Britain (see CA 368).
Uist Unearthed allows users to explore Cladh Hallan as it might have looked approximately 3,000 years ago. Our model reflects evidence that the roundhouse walls at the site were made from a mix of sand and stones, and it seems that they were not very tall. The space between the inner and outer walls was filled with sand and reinforced with animal dung, which stabilised the walls and stopped wind and sand blowing in from the machair. Although roofing material from the roundhouses did not survive, it is likely that they would have been primarily made from driftwood from the beach, and turf and marram grass from the machair.
The making of Uist Unearthed
Creating our 3D digital reconstructions was a painstaking and detail-oriented task, comprising the virtual construction of a building from the ground up, based on dimensions and architectural features known from previous archaeological excavations – particularly the SEARCH project. Studies of comparable buildings, consultation with period specialists, and extensive meetings between the project team, the excavators of the sites, and the modellers allowed us to reach a final reconstruction based on a truly collaborative process. These prompted fascinating discussions on subjects such as roof pitch and door heights, which challenged our preconceptions of how people used these spaces thousands of years ago.
From there, the models were brought to life through ‘texturing’, where the building materials and textures were added. Cosy hearths with flames and sparks added additional depth and atmosphere to the reconstructions, and the final step was furnishing the interiors with objects and other features to explore. Detailed plans from the excavation reports allowed us to place 3D models of artefacts in the exact locations they were originally revealed by the excavators. Many of these features are interactive, containing layers of text, audio, and photographs, which help to open a window into the past.
Collaboration, co-production, and engagement
While this project was delivered by Uist-based archaeologists at UHI, the wider team includes our partners at Comhairle nan Eilean Siar, Ceòlas Uibhist, and digital designers at PEEL Interactive. The success of this project, and the richness of its outputs, are due in no small part to the extensive collaborative process between the project team and our communities. This process began with extensive beta-testing workshops in 2020, where community groups, friends, and colleagues put the app through its paces before release. Tech-savvy primary and secondary school pupils were among our toughest critics – but the tests led to incredibly useful feedback on technical detail, reconstructions, and useability, which was implemented prior to Uist Unearthed’s launch in app stores. As the release date approached, UHI music students composed and recorded a bespoke piece of music inspired by the project, About Time, which features in the app’s promotional video.
A series of longhouses were built at Bornais throughout the Viking and Norse periods. The first was built in about AD 900 in the middle of the Viking Age, and the last was built in around AD 1200, near the end of the Norse Period when the Western Isles were still part of the Kingdom of Norway. They were signed away in a treaty to the Kingdom of Scotland in AD 1266. The final house to be built at Bornais is very different from all its predecessors in terms of shape and orientation – it is possible that the people living there had adopted a more regional identity, and identified more as Hebridean than Norwegian.
The settlement at Bornais was excavated between 1996 and 2004, by Cardiff University. Four of the mounds were investigated, uncovering a range of settlements spanning the Early Iron Age to the Late Norse period (from around 700 BC to AD 1200). Unpicking these layers of activity proved complicated because many of the structures had been built into earlier remains. Objects from the Iron Age had become muddled together with Viking artefacts, making it difficult to create an accurate timeline of events. A grid-based strategy was used in the excavations here, allowing the archaeologists to reconstruct the floors of the houses and learn more about where certain activities took place. This was especially important for the second longhouse, where the inhabitants had carefully laid objects on the floor in specific places. The archaeological assemblage from Bornais is one of the largest from the Outer Hebrides.
Uist Unearthed features the 11th-century longhouse at Bornais. Based on excavated material, our model shows a low, stone-walled structure with a large timber frame. Layers of turf encase the house to form the walls and roof, which has a hole above the hearth to allow the smoke to escape. Inside the house, timber walls separated it into three main spaces – two end-rooms and a long hall in the middle. The hall had a long passageway running through the centre, with two aisles on either side that were used as areas for sitting, sleeping, and other activities.
We also held a series of workshops with local schools to brainstorm and create content for the app – for us, highlights included a collaboration to storyboard and create an animation with the pupils of Sgoil Uibhist a Tuath, and a series of finds-handling and -recording workshops in collaboration with curators from National Museums Scotland. Participants from the Uist Community Archaeology Group and local historical societies took part to help showcase finds from Cill Donnain Iron Age wheelhouse and bring them to a wider audience. This included 3D photogrammetry workshops, taking a series of overlapping photographs of each artefact before processing to create 3D digital models that now feature in the travelling Uist Unearthed multimedia exhibition.
Gaelic is also an important part of the project. As the language of the region, Gaelic has a fundamental role in effective interpretation of the archaeological landscape of the Outer Hebrides, and we have strived to explore this as much as possible within Uist Unearthed. All the app and exhibition content is bilingual, and Uist voices – from crofters to musicians – reflect on aspects of landscape, place, and culture through Gaelic stories and song within the app.
Since its launch, we have showcased the app and exhibition to visitors, hospitality providers, community groups, and schools, and the virtual-reality headsets have proved particularly popular, capturing imaginations and immersing users of all ages. There is nothing better than seeing someone’s face light up as they crouch down to peer through the door of a (virtual!) 3,500-year-old Bronze Age roundhouse, or dodge the crackling fire at Viking Bornais.
Cill Donnain is an Iron Age wheelhouse – a kind of roundhouse unique to the Outer Hebrides and Shetland, so-called because in plan the piers look like the spokes of a wheel. The example at Cill Donnain was constructed towards the end of the Middle Iron Age, around AD 300. People continued to live in wheelhouses into the later Iron Age, building smaller, simpler houses in the ruins of their predecessors. At Cill Donnain, the wheelhouse eventually collapsed and a small structure was built in the north end. The remains of the wheelhouse were later filled in by people living in a nearby settlement.
The site was excavated by the University of Sheffield between 1989 and 1991. The location of the wheelhouse is known as An Sligeanach, meaning the ‘shell place’, and probably refers to the shell midden associated with the Iron Age structure. This refuse heap, made up of discarded limpet and periwinkle shells, was one of the first discoveries made by the excavation team – and, initially, it was thought to represent Mesolithic activity, dating to the period before farming was practised.
This proved the most-challenging site for our team of modellers to recreate in 3D, given the complexity of wheelhouse architecture. To build wheelhouses required specialised knowledge, and they were well suited to the climate of the Outer Hebrides, as the design provides an innovative way of roofing a large structure requiring only a small amount of timber. Our understanding of the prehistoric environment suggests that wood was a relatively scarce resource in Iron Age Uist, and the internal piers were corbelled to form cells around the edges of the house, reducing the area to be roofed with timber and thatch. In our model, these cells contain 3D reconstructions of artefacts to explore. Wheelhouses were only a single storey high, and many on the machair were semi-subterranean, or built into the ground, which protected them from the strong winds. Unusually, the Cill Donnain wheelhouse appears to have been built freestanding, making it more akin to the moorland wheelhouses on the east side of Uist.
The Uist Unearthed app is free to download from Apple and Android stores. It was created as part of the Uist Virtual Archaeology Project (UVAP), delivered by archaeologists at UHI Outer Hebrides with Comhairle nan Eilean Siar. The Uist Virtual Archaeology Project is supported by the ERDF Natural and Cultural Heritage Fund administered by NatureScot, The National Lottery Heritage Fund, Comhairle nan Eilean Siar, and Stòras Uibhist. The app and multimedia exhibition were created with PEEL Interactive with Gaelic content by Ceòlas Uibhist. Thanks, too, to Dr Fraser Hunter and Dr Hugh Anderson-Whymark from NMS; Professor Mike Parker Pearson, UCL; and Professor Jacqui Mulville, Professor Niall Sharples, and their team at Cardiff University.
How can you explore these amazing sites? Firstly, download the Uist Unearthed app (on iOS or Android). After downloading the app, scan the QR code at any of our sites with your smartphone, and the life-sized digital reconstruction will then come to life on your screen. On entering the virtual reconstruction, you will encounter a richly furnished interior: watch smoke rise from the crackling fire, explore archaeological finds, uncover facts, and unearth mysteries.
Keep your eyes peeled for our pop-up exhibition, and the addition of two new site reconstructions on the neighbouring island of North Uist: Dùn Torcuill and Dùn an Sticir.
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Snap and share your discoveries using #UistUnearthed
Dr Emily Gal is Project Coordinator for the Uist Virtual Archaeology Project, and lectures in archaeology at UHI Outer Hebrides.
Dr Rebecca Rennell is a lecturer in archaeology at UHI Outer Hebrides, and is Uist Virtual Archaeology Project Manager.
ALL IMAGES: Uist Virtual Archaeology Project, unless otherwise stated.