Neolithic Temples of Malta: 3D analysis points to novel roof reconstruction Madeline G.P. Robinson * , Augustine Porter, Will Figueira, Roland Fletcher University of Sydney, 2006, Australia ARTICLE INFO Keywords: Photogrammetry 3D modelling Maltese temples Neolithic architecture Digital reconstruction LiDAR ABSTRACT The Neolithic temples of Malta are among the oldest examples of prehistoric architecture, yet the construction of their roofs remains a mystery. The absence of any roofs or roofing material at the temple sites has resulted in conjecture regarding the original appearance of these megalithic structures. The most valuable indications of prehistoric Maltese roof architecture are found in the Neolithic burial complex, the Hypogeum of Hal Saflieni. Two chambers in the Hypogeum are modelled closely after the above-ground temples, with indications of a roof structural system on the ceilings. This paper uses LiDAR and photogrammetry-derived 3D models to provide a partial temple roof reconstruction that has its design entirely based on contemporaneous archaeology. Photogrammetric reconstruction of the Mnajdra and Tarxien temple complexes allowed for detailed archi- tectural analyses including key structural features and any indications of previous roof construction that would be evident in situ. A LiDAR model of the carved chambers of the Hypogeum of Hal Saflieni was superimposed onto corresponding positions in the temple models. Merging the LiDAR imagery onto the photogrammetry temple models confirmed structural consistency between the two megalithic complexes; supporting the theory that the carved façades were a deliberate reflection of the original architecture of the Maltese temples. This evidence points to an entirely new temple roof reconstruction, founded upon the archaeology of Neolithic Malta. 1. Introduction The Neolithic temples of Malta date to c. 5,600–4,500 BP yet a sur- prising number of them have survived. Spread around the two main islands of Malta and Gozo, these megalithic structures are the oldest still- standing monuments on record (Stroud, 2013). One striking and consis- tent feature shared by the Maltese temple complexes is the absence of any evidence of roofing. With no apparent roof material found around or within the temples, the form of the roofs has been a matter of intense debate. Determining the original roof construction for the Maltese temples is important as it provides insight into the engineering capabilities and construction methods developed by an isolated prehistoric island society. This paper uses 3D reconstruction of the remaining archaeological representations of the original temple architecture to demonstrate the viability of an alternative roof structural system for the Neolithic Temples of Malta. Photogrammetry models of the Mnajdra and Tarxien temples were created for analyses of the structural arrangement and megalithic engineering to identify any indications of previous roofing structural systems. Photogrammetry is an established method of accurately digi- tizing artefacts for archival and analysis purposes (Lerma et al., 2010). The diverse capabilities of 3D technology are becoming an invaluable method of structural analysis of small and large scale objects in archae- ology, allowing for fast recording processes, detailed documentation and interactive visualisation. The Mnajdra and Tarxien temples were chosen for their optimal states of preservation, the quality of photogrammetry model produced and important architectural clues. The size, complexity and fragility of the structures are not conducive to easy visual survey on site. The methods involved in digital rendering do not impact or disturb the sites and are a reliable approach that enable multi-directional and multi-scalar analysis of the monuments and the detection of key struc- tural detail easily overlooked by simple observation. Recording could be carried out in any direction of angle of view without impacting the integrity of the building. For example, tops of walls and large stone slabs could be recorded without climbing on the structures. High-resolution photogrammetry was therefore an ideal method to conduct intensive analyses in preparation for configuring a new roof reconstruction. The most informative evidence for Maltese temple roof architecture lies in the Hypogeum of Hal Saflieni, an underground labyrinth of rock- cut tombs dating to 5,300–5,000 BP. Fortunately for the interests of this investigation, two chambers in the Hypogeum were carved with the same fundamental design. Decorating the chamber walls are life-size repre- sentations of the interior architecture of the above ground temples. With * Corresponding author. 22 Fox Road East Ryde, Sydney, Australia. E-mail address: madeline.robinson@sydney.edu.au (M.G.P. Robinson). Contents lists available at ScienceDirect Digital Applications in Archaeology and Cultural Heritage journal homepage: www.elsevier.com/locate/daach https://doi.org/10.1016/j.daach.2019.e00095 Received 1 December 2018; Received in revised form 1 March 2019; Accepted 18 March 2019 2212-0548/© 2019 Published by Elsevier Ltd. Digital Applications in Archaeology and Cultural Heritage xxx (xxxx) xxx