 So thank you first for having me. At that point, thank you for the invitation to present to archaeologists. I am not an archaeologist. That's how I have to excuse the beginning. But my subject has to do more with the history of technology, that is my perspective, my goal, and touches several points of archaeology. And I will have to explain the beginning. So my initial goal was, or is, the question how certain communities in China, in particular mostly Muslim communities, organized in the past and still organized in the present, there are technological activities, in particular, building dwellings that are known as cave dwellings, Yaudong. Now, this includes also planning, construction, and maintenance, that is, what is and was my goal. And even if positioned in the present, my research has at least two levels touching archaeology. Archaeology first, because these dwellings already exist, or not these dwellings. Then this description, the description of such dwellings corresponds to prehistorical dwellings that exist in that area for geological reasons. And the second level of contact is the fact that the criticism I will explain towards the end of the presentation is inspired by prehistorical archaeology. So first I will explain somehow the geographical frame. So the Les Plateau, across the Yellow River in North Central China. Some comments on the conventional typology of these dwellings, I use the Chinese term, Yaudong, because it's so polysemic that can include almost everything that you will see. Then these flooding evolutionary approaches, and then the criticism I promised at the beginning to come to some conclusions, which are more open questions and statements. What you see here would be one of the categories, but one of the categories of that sunken courtyard. We are in North Central China. I apologize for the math. You see Beijing, so here the sea. China goes another to the west, the desert of Panakang, the Xinjiang. And we have here the Yellow River Pankhu. She is known for the terracotta, and also for one of the Neolithic cave dwellings that I will comment on in the following. And you have here the valley, which is dominated by this wind-carried sediment, sand, that forms the less sediment and is subdued to spark erosion processes, and is the place where the geologic formation, which is characterized, but where these dwellings are characterized. So we have China, that is the province, which contains Xi'an, on the northern China sea, then the autonomous region of Guangxi, but also with the Muslim population, the Gansu going to the northwest and to the east. I said that this term was used in the pin of the 20th century in archaeological research to characterize pit caves found near Xi'an, how you can visit it almost in the city of Xi'an. Pit caves that were reconstructed might have had also a roof. So every Neolithic, but probably exist in stealing the Mesolithic and eventually in the Paleolithic, late Paleolithic period. Some types of Yao Dong to see the variety of these constructions that they are all made. So the first one, well, first I have to say there's no single pit anymore, like I showed in the previous story. But we have this kind of sunk and courtyard, the pit cave dwelling, some architectural historians call it like that. We have the cliff side, built in the cliff cave dwellings. We have the semi-below ground dwellings, the combination of both. And the term is also used for these kind of independent, hooked dwellings. I will explain somehow about the construction and then combinations open end. The most typical from my point of view are the cliff side dwellings, the artificial cave dug into cliffs and sometimes with an extension outside the cliff. The sunken courtyard, some called pit cave dwelling, has a roof which is considered by the ground. The pit is dug into the ground and the dwellings are lateral. The cave dwellings are dug into the lateral surface of the pit. Before explaining the way of constructing, which helps more to differentiate between these artificial tip typologies, some words concerning the so-called hooked dwellings or independent dwellings, they are mostly based on the sunken front yard. They are built by bricks of round earth excavated on side that is loose. They are covered by the same material, low-soil or round earth, generally structured by wooden beams, so wood still does exist in these particular cases and these type includes also art constructed with bricks made by adobe or sometimes today by stones and they exist where no cliff neighborhood is seen. They are considered by some architects to simulate a cave, therefore these term constructed caves may be found. Now there is a heavy ideology going from the Neolithic to the present concerning the process of development, the single pits, although this series is not so continuous, there are intermediate steps archaeological is still missing, but it is a dominant idea in the historians of, especially Chinese historians of the Chinese house. The other premise is that the logical premise of emerging from the ground as a progress, civilization progress and this could be a possible itinerary reproduced in history of Chinese housing. And there is also the valorization of the material of soil and the valorators of rocks as the soil and rocks as primitive materials wooden structure of something more noble. Sorry, now I have skipped something. Concerning the evolutionary approach, the evolution, archaeologically there are these evidence of multiple paths and multiple evolution paths even during the Neolithic and afterwards. So the dwelling that comes out of the ground where the soil is seen as a material of continuity but also digging down with the experience of having the houses above the ground and simulating the housing above into the ground and especially lateral constructions of the something courtyard. So it is somehow a revalorization, revalorizing the cave, going into the cave with the experience of the overground. The formative apology I showed you has been a photograph, but if you try to reconstruct the process of construction then you structure the the typology in a different way especially concerning that sunken courtyard because there you go in the cave exactly as you do in the cliff, only you create a cliff. So I will go into some details of the construction for this revalorizing the presented typology. The categorization of material, the categorizing criteria would be the material or could be structural similarities without with other buildings. I mentioned something with the roof and there are works where this the construction, this independent the so-called constructed caves, the independent the hooked gyaodongs are compared with traditional chinese houses and they they make a quite different sense than the one that I presented here. The social space, the ethnic groups inform what is about my interest. I will explain some aspects in the main course and some have to remain still as questions especially the symbolic infection of digging a pit or digging a hole with the inspiration from the prehistoric theology of Baili. Now I said that the constructing process gives another idea of how it becomes what it is called especially the fact or time that is absent in the typology I presented. The construction of the cliff cave is more easy to have here to make a flat then you begin to dig the caves at the end you have the arcs, the construction of the inner circles and if there is any course here that would be added. What is I found more interesting is the construction of the sunken cave. You do not make a hole hole you just make a trench and then you begin with the holes which we do not see here then you remove the the main bulk of the bulk of the masses you move and in several stages they continue to dig the hole. What seems to be interest and I say seem it depends if you ask you get the answer if you don't ask you just oversee that. It's the fact of time. Time for what? For letting the moisture go out. If you ask how long does it take? How many people do you need and so on? Then you couldn't make a rational equation because it is not only how much labor is needed it is also related to the time how much time you need to get the moisture out of the hole if you want to to work there or if you want to stay there. So how long it takes? You can find very diverse answers in the literature from three weeks to three months to three years depending on how you put the question and for me as an engineer this removing the moisture becomes a leading factor it's not how it looks like is it the hole or is it the rectangular or whatever and it has of course a quite different symbolical value than the appearance. Talking about the material the bricks I mentioned for the for instance the independent the Houtma and Yaudon they are made from the same material so in somehow you continue you can say the material continues from the earth and becomes an artificial cave that is the reason why Jean-Paul Loupe considers that artificial cave the construction over the earth as a continuation of the digging process and what is for me also interesting is in this photograph and modern photograph how many persons are present I don't say engaged that would be a false question how many persons are present and we will see another photograph you can count the person this is I'm talking about the social space which is more or less neglected in the literature this is an old or 17th century woodcut for the constructing of a round-earth wall it looks very similar that is from in one of the compendia of the main and of the main because of the changes in the 17th century onward and supported by Joseph Neatham as a history of civilization science civilization in China in the 50s to say all the similarities this existed or there this is a photograph from Jean-Paul Loupe in the 80s 90s and again I do not know whether all these people can work there you would find some notions and some remarks in the people in literature reporting this process of constructing in the sense that the constructing of the Yaudong needs a social solidarity of mutual help I think it is not so much helping just sitting there staying there I would say this is a materialization of social memory of the people who are contributing in the social process of building what they are doing of the building what is building their own the bricks fabricated in the previous photograph and so to conclude I try to go beyond the factual interpretation and ideological pre-assumptions of the process of civilization trying to find anthropological approaches and anthropological questionings some are already some questions or some comments of this art are already present in history in the work of Jean-Paul Loupe with the history of architecture and anthropologists at the same time saying that pit dwellings is a stage in the development of people's attachment to the land is more than leaving the pit for the past and it is precisely prehistoric archaeologists who put the question what does it mean to dig to build a hole cutting the surface is a book that you can find in the fair here 2018 appeared constructing a ramped earth wall or constructing an amount of pre-executor I can be considered and analyzed as an interaction process inside a given community now I come to my Muslim community my communities it is not the religion that interests me it is that the way certain local communities organize and the participation in the communal work it could be guided by the local leader and the local representative of the communist part but how they organize this day the next day they are the day what happens on Friday and things like that that can be very particular and very attached to the local community and what does it mean to to give the the notion of continuation of the memory and that's why I mentioned here the way the Muslim community of Ninsia in organizing and symbolically connoting the digging and constructing actions that has to be still elaborated thank you for your