Interesting project from New York University, mapping around 200 cities worldwide in 1990, 2000, 2014

UK urban policy institute that monitors the economic health of cities.

Also from the EU, see the City Centres Database, reportedly the most detailed in the world.

UN agency seeking to improve urban conditions, especially in developing countries.

Project from Data Driven Enviro-Lab, detailed satellite & geo-spatial & data on social & environmental issues for cities around the world

UK-based project linking cities worldwide in showcasing the importance of culture to policymakers