Buildings, Collada models
Display houses and buildings available in the Collada format.
More efficient then direct support for Collada format would be to convert the models in advance into JSON files:
The initial implementation should probably load the model and locate it in a correct place on Earth programmatically.
For efficient displaying of whole town composed of larger amount of models a server side preprocessing or dynamic streaming must be implemented - with several level of details (generalized version of model for distant view, detailed for close view once it is loaded).
I we need something like: http://www.youtube.com/watch?v=rGLInTXTdNI#t=07s then prerendering of descreet areas of town should be done. Think of mercator tiles, but with 3d content instead of raster data.