A current challenge related to 4D viewers at world scale is the low number and geographic and temporal coverage of 3D models available. To overcome this issue, we work on different tools to (1) harvest 3D models, images, and location-based information from multiple sources via automated and community-based approaches; (2) automatically process these into 4D cityscape models; (3) make the 4D models accessible in two visualizations: via a 4D browser and a location-dependent augmented reality representation. Since previous articles report on the pipeline, tools, and usage scenarios, this contribution highlights ongoing developments in (1) large-scale 3D data retrieval; (2) 3D mesh model and LiDAR processing; and (3) novel view synthesis via Gaussian Splatting. The datasets are viewed in two 4D world viewers for (4) desktop browsing and (5) location-based mobile use. To date, they have been tested in seven countries.