## 4 Discussion and Conclusions
It is important to emphasize that such information alone is not sufficient, and it needs to be processed by experts, but also supplemented by other data relevant for damage assessments (e.g., structural system, function, and usage). A compilation of all the data can be obtained to get a unique view of the seismic vulnerability of existing structures. A combination of the data from \"traditional\" assessments with the results from modern techniques can help us in the identification of weak structural parts and components (faults, big cracks, and openings, short cantilevers, and walls, short columns, soft storeys). With the knowledge of the architectural background and styles of the city, a quick estimation of the period when the building was built can be obtained, i.e., in Croatia, tall windows can tell us that the building was built during the Austro-Hungarian times. This data can relate to construction methods, wooden ceilings, lack of glazing and confiners, greater wall thickness, different material quality, etc. All these important factors are influencing the seismic behavior of the existing structure. With measurement data of foundation settings, soil stiffness can be assessed or may indicate some differential settling. In addition, the building stiffness can be estimated, which can lead to an estimation of the number of internal walls. Assessment of roofs with UAVs can identify the deformation of roof plates and can serve as a basis for the identification of internal walls, which can also lead to estimation of stiffness. With thermography, different building materials can be identified (masonry vs. concrete) and existing confining elements with their dimensions and location in the structures can be pointed out. With a combination of methods, and estimation of wall thicknesses (with basic geometry) quick interpretation of structural safety can be estimated. Deformation of outer walls obtained by photogrammetry combined with energy losses by thermography and architectural rules of the construction period, and with expert opinions can lead us to a rough estimation of the number of walls (considering the knowledge of load-bearing plate system). All of the mentioned activities can give us the level of seismic vulnerability and safety of the existing structures. The obtained data, new procedures, and techniques can help us in the estimation of seismic risks of bigger regions or building blocks (Figure 4). A conceptual design of building blocks can be easily identified (weak parts, floors on different heights, and influence of one building to another), which gives the information of seismic risk. The development of a modern procedure for structural damage detection and estimation of seismic risk and vulnerability must be improved with new and accessible technologies. **Author Contributions:** Conceptualization, M.S. and M.G. ; methodology, M.S. and M.G. ; validation, M.S. and M.G. ; formal analysis, M.S. and M.G. ; investigation, M.S. and M.G. ; resources, M.S. and M.G. ; photo credit, M.S. and M.G. ; writing--original draft preparation, M.S. and M.G. ; writing--review and editing, M.S. and M.G. ; visualization, M.S. and M.G. ; project administration, M.S. and M.G. ; funding acquisition, M.S and M.G. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was partially funded by Croatian Science Foundation, grant number UIP-2019-04-3749 (ARES project--Assessment and rehabilitation of existing structures--development of contemporary methods for masonry and timber structures). This work was supported by the University of Zagreb for the project: \"Advanced photogrammetry and remote sensing methods for environmental change monitoring\" (Grant No. RS4 ENVIRO). **Conflicts of Interest:** The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.