Prof. Paolo Gamba is going to deliver an invited lecture at the Istituto di Fisica Applicata of CNR in Florence on this coming Thursday, Oct. 26. The seminar is devoted to explain why the use of multiple sensors is mandatory in urban areas, at multiple spatial and geographical scales. It will also provide a few results or urban area extent characterization at the regional/national level for different urban areas in the world, considering fusion of Sentinel-1 (SAR) and Sentinel-2 (multispectral) data, as well as Sentinel-1 (SAR) and Night-time lights data.