This is not an Opera House

This following image is really the sum of the multiple scattering of sun light on a known Parisian landmark. 

The question: What can we do with 1 billion GPS-internet-enabled cameras ?

While some did the extraordinary work of figuring out the geolocalization of a scene based on common features, this problem is now solved if pictures can be GPS-stamped. Hence the information obtained is really about the environmental conditions (aerosols, sunlight,...) when the photograph was taken.