Longue Durée: Perceiving Heritage Through Media Architecture

Media architecture increasingly shapes the mediation between cultural content and visitors in heritage sites. This pictorial examines the potential of the heritage building itself to act, through media architecture, as a presentational object to trigger a more inclusive way of tracing the past. We present the design, implementation and effects within an ancient monument at the foot of the Acropolis, Athens. Using a multimedia projection of animations, combined with sound effects and narration, this novel work fuses the building walls and media projection to reveal the ancient monument's layers of history, and communicate the cross-cultural encounters across time. We discuss key design insights, with a focus on media content development from a museological-conceptual and architectural-spatial points of view, and, based on visitors’ response, argue that, by adding a richness of perception and presenting the past “as a field of experience”, media architecture introduces visitors to new modes of seeing and experiencing heritage sites.


INTRODUCTION
Heritage sites and museums are changing from objectfocused to people-centered and participation based, and are aspiring to be experienced as inclusive, diverse and engaging environments.In this pictorial we present the initial explorations of MUSEE, an interdisciplinary project that aims to study the interaction between spatial layout and digital experiences, and the effects of this interaction on key dimensions of visitors' experience.The first phase of the project focuses on the Tower of the Winds (or Horologion of Andronikos), at the archaeological site of the Roman Agora, Athens.
Built at the end of the second century BC as an astronomical and weather station and a "clock tower", the octagonal building has a long history with different uses, including being a sacred place for different religions -a place of worship for Christians and a place for prayer for Muslims.Today it is regarded as the bestpreserved ancient building in Greece.
Since 2016, it is open to the public, after years of restricted access.In parallel, it constitutes an urban landmark and a point of reference for contemporary citizens.
The use of digital technologies in heritage sites to add layers of digital information over the physical environment, is accelerating in recent years.This may form different kinds of experiences, for instance, through the use of Augmented Reality-based experience to discover information about past life in a threedimensional form, to provide a highly engaging and compelling local heritage experience [12] and to support situated learning when situating digital archive in the actual location of the events they represent [17], or the use of interactive projection mapping to reproduce and uncover layers of historic wall designs in a town house through a wave with the hand [24].
Projection mapping, also called Spatial Augmented Reality (SAR), when applied to cultural heritage offers new opportunities for spatial storytelling, as a hybrid with traditional museographic systems or with mixed reality systems.It is often configured as the best action to be interpreted to communicate the past as it frees the user from other systems [19].Many heritage buildings are often listed buildings, and as heritage concerns prevent major interventions, a projection system is less obtrusive and more flexible, and can support the creation of various effects [7].
Media Architecture scholars have addressed potentials and challenges for using projection mapping on buildings and objects in museum settings [11,27].Among others, Basballe and Halskov [1] and Dalsgaard and Halskov [3] have used 2D and 3D projection on museum exhibits, identified and proposed sense-making, engaging conversations and playful engagement as three general ways visitors engage with the installations.Other types of behaviours we observed over the years, in particular with large projections, include very often posing for a single or group photos and creating new visual narratives or an extended one as part of the visual content; also common laying on the floor or sitting on the edge of the space to view the projections from a selected angle.
More importantly from the point of view of this research, Nofal et al. [20,21] who coined the term "phygital heritage", have implemented interactive projection mapping to reveal different building phases and functions of a chapel and outlined how it positively impacts visitors' understanding and memorability of the aesthetic features of architectural heritage.However, opportunities offered by time-based "passive" storytelling through situated immersive projection, to communicate historic information of a complex past, have not yet been fully explored.
In this project we focus on the effect of the projection and how the projection, through the creation of a time-based narrative that relates to the history and tracing of the material history of the past, can reveal the invisible and tell the building's story.More importantly, we capture visitors' reaction and response about using this novel way to communicate the complex and intertwined layers of the past and to reflect how the building was used and inhabited by different people and cultures who occupied this monument on that site over a long period of time.
The theoretical framework of this work is on the one hand the increased awareness in museum/heritage theory and practice of the significance of space in the creation of the experience as well as its understanding [6,10] and on the other hand, the concept of "embodied understanding" [13,18], which has led to the increased engagement of museums and heritage sites with embodied, sensory and emotive forms of knowledge.
While drawing on this body of literature, the project also positions itself in the field of previous media installations exploring projections on historic buildings (see above).The media project in the Tower of the Winds uses projection of animations and graphics in the interior space of the monument, combined with music, sound effects and narrative sections.It fuses building and projection to reveal the ancient monument's layers of history, and communicate the coming together of very different people, cultures and functions.The work can be thought of as novel in its combination of being projected on an ancient monument, dating from Greek antiquity, and using the traces of the past, of different periods, often overlaid on the physical fabric of the building, to narrate its complex history.Thus, through media architecture, the heritage building acts both as the object of display and as the means for the interpretation of its past.
In this pictorial we present and discuss key design concepts, intentions and choices, and draw insights from our investigation and observations, which was conducted as part of the 2022 European Heritage Open Days, between 23rd and 25th September, in Athens.We make two contributions: first, the research offers a reflectiveaccount on the creation of the digitally mediated experience, mainly from a museological-conceptual and architectural-spatial points of view; second, based on visitors' responses, it illuminates how they perceive the interaction between physical and digital space and use this to construct embodied and affective meanings.The ideas and findings set out in this pictorial, offer insights for the design of media projections on heritage buildings, by bringing to light particular challenges and new potentials and suggesting a better understanding of the effects of design choices on visitors' experience.

Longue durée
Inspired by Fernand Braudel's concept of "Longue durée" (a perspective on history that extends deep into the past) [2,26], the key concept for the digital content design is that of long duration, both in the sense that the monument has to do with thousands of years of history, and our time-based media installation reflect this; and in the sense of slowing down the time of "reading" and prolonging visitors time of stay in the monument, by attracting attention to meaningful details and heightening the sense of being physically present in it.

Inclusivity
Related to this is the notion of inclusivity, in that the installation, by taking a diachronic perspective, brings to the fore important aspects of the city's past which tend to be less well represented, as for the example the life of ancient monuments and heritage sites after Antiquity [22], or the still rather marginal field of Ottoman history and archaeology in Greece [16].
Inclusivity is also reflected in the use of audio-visual storytelling to support wider accessibility instead of using conventional text-based information, which is common in museums and heritage sites, where the aim is to address wider audiences with a range of background knowledge, including international tourists.

Accessibility
A double meaning is also given to the fundamental concept of accessibility.As analyzed below, the project addresses both intellectual accessibility, by seeking to communicate meanings in an easy to follow and enjoyable way through animation, as well as spatial accessibility, by analyzing the spatial layout of the building.

THE MEDIA ARCHITECTURE CASE: THE INTERTWINED LAYERS OF HISTORY AS ANCHORS FOR THE CONTENT DESIGN
Two thousand years ago, in the commercial centre of ancient Athens, the Tower of the Winds, designed by the Greek architect/astronomer Andronikos, was a landmark in the city [14,15,25].
At the top of the roof, there was a bronze rotating weathervane, in the form of the god of the sea, Triton, which indicated the direction of the wind.
It operated in combination with the representations of the wind gods on each of the eight sides of the building.The eight wind gods are depicted as winged male figures.
Each side had also a sundial.The engraved lines for measuring time are still visible today below the relief figures of the winged winds.The sundials served the tradesmen and the other Athenians, which used the commercial centre of the city, in the area later occupied by the Roman Market.
In the interior of the building, traces of pigment of Egyptian blue on the surface of the ceiling suggest that it depicted a starry sky.
Cuttings in the floor and a conduit beneath it allow the hypothesis that a water -run mechanism once existed here.It functioned by means of water pressure coming from the small circular space, visible in the background.According to the most recent interpretation, this mechanism set in motion an armillary sphere, and the building served as a "planetarium".
The graffito on the wall representing a roman shipan invocation perhaps to the god of winds for safe sailing -can be thought of as a nod left in time.
The flow of time brings changes to the building's function.Fragments of wall paintings, which were discovered recently, indicate that the building was used as a church in the Byzantine period.
The building is then re-used as a tekke, a gathering place for dervish dancers, as documented by the remains of a "mihrab" niche, a prayer-niche, carved in the wall.
Regarded as the best-preserved ancient building in Greece, it continues to be a point of reference in the city for its citizens and visitors alike, a compass in time and space.

Access and understanding
The project was conceptualised so as to make the ancient monument more accessible intellectually to citizens and tourists alike.Though it is located in a central location in Athens, and in particular in the commercial centre, and is a familiar landmark for citizens, many might not have intentionally visited it or been aware of its functions over time.
The installation was designed with the aim of contributing to visitors' embodied understanding and appreciation of the building and its layers of history, by focusing on key points of its past and compressing events that took place over centuries into a single spatial and sensory experience.
The idea that the primary means for "explaining" the monument is to let it reveal itself was the starting point of the design process.
The use of traces (drawing with digits on these material traces, literally) more or less visible on the physical fabric of the building, and the careful alignment of the projection on the building and its meaningful details, are distinguishing features of the installation.
Viewers can scan with their eyes walls, floor and ceiling from a viewing platform.
Here we show focal points of three different visual planes.
The entire space is treated as a single situation into which viewers enter.
The spatial affordances of the small-scale building, in combination with the specially designed soundscape, are used to create an immersive and all enveloping sensory experience.

Balance between the intellectual and experiential
Among the key museological challenges, was also to communicate the richness, complexity and distinctive character of the monument in an engaging way by inviting visitors to "look, listen and feel" [29].
To this end, it was important to balance between the intellectual and experiential, and between the need for scientific rigour and our creative imagination (see design choises below).

Representing spatial experience
To represent spatial experience in the building, we use both the urban HCI framework [8] and spatial configuration analysis methods and concepts [9].
The configurational analysis is carried out using the DepthMap software [4].Analyzing the plan as a pattern formed by the visual fields that we see from each point, we can describe the complexity of visual steps from each point to all others and show clearly the pattern of differentiation between the parts or points that make up the layout.
The resulting pattern of visual integration says how difficult it is to get to see all the space in the layout of the monument from each point.The colours -from red for the most integrated (or easily accessible) through to blue for the least -allows us to see at a glance the pattern of integration values in the layout, and make visually clear the hierarchical visibility pattern of the Tower and the contrast between two micro-spaces -the more integrated and visually accessible "display space" and highly segregated "potential interaction space" [8].
Restructuring space in the interior of the monument through media architecture (based on the space type mode for unban HCI proposed by [8]).

From an implementation point of view
Finally, in terms of the deployment and technical aspects of the installation, the Tower of the Winds, as a historic building, inevitably sets requirements and imposes its own restrictions on the implementation of the installation, and in particular the location of projectors and the interaction style, in addition to the scale of the media screen (7m X 24.2m), the control of lighting and external sounds (as the interior is essentially an open space), and poses difficulties in terms of ensuring the availability of appropriate infrastructures.

Componenets of the media installation system
The installation consisted of five high-definition (4K) and high-brightness (12,000 Ansi Lumen) projectors, and a 5.1 3D surround sound system.The system was managed by a Mac Mini type computer and an external graphics card.The projectors (3+1+1), used for the projection on the walls (throw ratio: 0.6), the ceiling (throw ratio: 1 -1.2), and the floor (throw ratio: 0.6) synthesize a total of 130° of vertical visual field extent and around 85° of horizontal extent, and a projection "screen" resolution of 1920x5400 pixels.
The audio-visual storytelling, in two versions (English and Greek), lasted for 6 minutes and repeated in a loop from 8:00 am to 15:00 pm

Framing and open-endedness
The key design choices were consistently guided by historical evidence and based on the study of sources (such as texts of travelers) and visual representations.At the same time, the work sought to shape a poetic performance and an open-ended message that set the monument in the everyday life of citizens and situated the visitor in the flow of historic time.
For example, the physical remains of a "mihrab", a prayer-niche carved in the wall which confirms the use of the building as a tekke, are emphasized by the digital projection, while the animation of a cultural dance makes a link between the building and its representation by the 19th century archaeologist and painter Edward Dodwell.Thus, the installation creates a visual illusion while it reveals, and combines the tangible heritage (the traces on the wall), and the intangible heritage of the activities that took place at this location (the dervish dance).

A visual adventure and a slow-paced rhythm of perception
The visual content was designed and superimposed on existing material traces on the walls, with the intent to invite visitors to look closer at the ancient monument and to reveal something relevant that they might otherwise have missed, either by accentuating what exists or by adding something to the space of the projections.
It should also be noted that, while it is designed to guide viewers in their reading of the interior of the building, at the same time, experiencing the work becomes an act of visual exploration and discovery, encouraged by the sheer scale of the building and the localized nature of the projections.

A rich acoustic experience
This is further enhanced by music.It was composed to fit and support the different elements of the installation, as for example to make visitors "feel" the passage of time, and in particular the historical/ cultural transition from the byzantine to the ottoman phase of the monument.
There was a sudden change in music style during the Ottoman period, an intentional change in tempo and music character to draw attention and emphasize the change of culture at the time.The music rhythm provokes children's response -dancing, clapping hands.
The acoustic experience is enriched by narrative segments (with the narrator, a female voice, describing the ancient monument in its various stages).
Audio and visual experiences point in the same direction to support and reinforce each other.
More importantly perhaps, they progress in stages, mainly focusing on one element at a time, so that the viewer is led step by step from one point to the next.This unfolding of the experience establishes a slow rhythm of perception and constantly refocuses visitors' attention.
The soundscape installation included a variety of types of sound, ranging : -from natural sounds (e.g.subtle wind and running water sounds) -to sounds describing activities (e.g.carving in marble) -combined with sounds of visitors' presence and social interaction (e.g.contemporary visitors talking an d takin g photos), so as to emphasize the sensory experience and enhance the sense of place [28].

Observation of visitor behaviour
The starting point of the research was the theoretical issue of how visitors respond to a novel and carefully designed media installation in an ancient monument, where new interpretation possibilities and visual and aesthetic means, are used to convey ideas about the building's material and immaterial traces and past.
Audio visual stimuli: the audio narration, in combination with the contrast between the bright exterior and the dark interior, created the first attractor.
The site attracted diverse people both locals and tourists/various age groups.A common behaviour was making sense (human-to-object interaction), gesturing/ pointing, and explaining to others (forms of person-toperson interaction mediated by the projection).Other types of behaviour included dancing, mediated through the change in sound rhythms and the use of music (human-to-medium interaction).
Spatial storytelling : The visual storytelling is distributed along the different planesceiling, floor and walls -and although most visitors were static, and predominantly among high density of people, they changed the head orientation following the narrative planes.

Research with questionnaire
The sample is made up of 200 questionnaires, filled in by visitors, who were approached at random at the end of the visit by three researchers.It consisted of closed ended questions, open questions, which are the focus here, and basic questions about the respondents' profile (including prior visit and/or knowledge of the monument).

Visitors' first impressions and thoughts
In many senses, the replies to the firs t open-ended question, about "visitors' first impression or thought", clearly reflect the visitors' positive approach to the media project and their thoughtful comments.More specifically , visitors' first impressions seem to affect their feelings and their curiosity, increasing their engagement and contributing to the enjoyment of the sensation of understanding: -I was curious to discover the history of the place.it was very beautiful and poetic.It was like a "conte de fées".
-It was like an exciting film or book that I want to see/read directly.
-I understand the use of the building.That was a nice feeling.
It can even change their initial concerns to a positive approach: -I'm sometimes a bit skeptical of historical/archeological visualisation, but this time it was very well done and took me in immediately.
-I was interested to see what sort of modern project could be achieved in an ancient monument (perhaps skeptically).I was pleasantly surprised.

Cognitive and affective engagement
When asked to compare their first impressions and thoughts to those at the end, visitors'"thinking aloud" about their experience gives insights into the interweaving of the intellectual and affective cognitive dimensions of the experience, the combination of the aesthetic and the intellectual point of view: -Une expérience à la fois instructive et poétique :) -Magical.Immersive.Informative and beautiful.
Visitors' comments are striking for their language of immersion, and the discursive expression of intense subjective feelings and emotions: -Very moving.Felt more appreciation than before.
-Relaxation, peace.I was feeling like I was in a space ship.
-I felt like I was transferred back in time.
It was very surreal to be standing there.

Visitors' intelligent discussion of the media project
The media project generates not only a positive response but also provokes an intelligent discussion of how it is designed and how it is working for visitors.
In their comments, visitors compare the audio-visual medium to textual information, and reflect on the way it augments space and enriches perception: -Showed details of building.A sign or just reading wouldn't be the same.
-I liked how the digital experience used the structure as a background and used projected images to teach about the purpose.It was much better than a sign.-How it did transform a building with nothing inside in a complete different story.
-It brings value to this place.In my opinion we can develop our perception.
More importantly perhaps, visitors perceive and enjoy the key features of the media project that can be thought of as creating its distinctive spatial, intellectual and social character -for example, the static nature of the experience, the collective dimension, the discreet use of colours, the unexpectedness of parts seen, and the sense of a heightened awareness of the interior space of the monument:

CONCLUSIONS
In this pictorial, we have sought to show the potential of a heritage building itself to act, through media architecture, as a presentational object to trigger a more inclusive way of tracing and experiencing the past.Framed by the concepts of "longue durée", inclusivity, and accessibility, our media architecture project was designed with the aim of contributing to "seeing" the monument's layers of history, and reinforcing the intangible aspects of the past, creating for visitors a heightened sense of being physically present and engaged with building details, which are scattered over its various planes (ceiling, walls and floor) There is also a larger potential relevance of this analysis which relates to the key insights from this work for media projections on heritage buildings.By suggesting a deeper understanding of the particular challenges and considerations -both from the content design and implementation points of view -and proposing ways of handling them, our project could creatively inform future designs.No less importantly, our empirical study illuminated how a diverse audience perceives the interaction between physical and digital space, and uses this to construct embodied and affective meanings.It demonstrated the ability of the media project to maximize the duration of stay in the monument, enriching perception and understanding, as well as its significance as a spatial experience, personal and at the same time highly collective.
It could then be said that media architecture, by presenting "the past as a field of experience" [23], can be seen as a mode of mediation with the past and introduce visitors to new ways of seeing and experiencing a heritage site, a public place.

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From an architectural-spatial point of view Tension between spatial accessibility and visibilityThe interior space of the monument is relatively dark, with two entry points and a few small openings.It is characterized by a tension between accessibility (visitors, maximum 10-15 people, stand on a glass floor panel) and visibility.While spatially enclosed, it is visually a powerful space.At the same time, the juxtaposition of open visibility and visual insulation from the outside, the closedness of the space, and its static rather than movement-oriented character, offer the preconditions that facilitate the assimilation and understanding of the intense local experience.Horologion of Andronikos of Kyrrhos -Ephorate of Antiquities of Athens City.© Hellenic Ministry of Culture/Hellenic Organization of Cultural Resources Development (H.O.C.RE.D.) (L.4858/2021)

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Photograph: Horologion of Andronikos of Kyrrhos -Ephorate of Antiquities of Athens City.© Hellenic Ministry of Culture/ Hellenic Organization of Cultural Resources Development (H.O.C.RE.D.) (L.4858/2021)] Seeking to understand the media project experience from the point of view of visitors, we combined observations of behaviour and a research questionnaire, over a period of seven hours on two consecutive days (24th-25th September 2022).Observations were carried out by two researchers.