Today we had a fruitful discussion on 3D city modelling with members of the Turkish Ministry of Environment and Urbanization and the Turkish company Argedor. They showed us a preview of the 3D city model they created for Istanbul: it contains all the CityGML LODs (from 1 to 4), and has textures. They also showed how the 3D data is being used in different applications and how important these applications are for the planning of new infrastructures, for example the a new metro line. Further collaboration will be investigated, also through our two Turkish research visitors: Elif Ozbek and Serpil Ates.