Google allows the creation of 3D models for buildings, with a concrete maximum level of sophistication, that can be viewed with the 3D buildings layer in Google Earth.
The buildings have to be modeled following special guidelines from Google and uploaded for approval.
Upon the model has been approved, they will apear in the aforementioned layer of Google Earth.
These 3D buildings also appear in the Google Liquid Galaxy, allowing a fantastic view of the cities in 3D that have this kind of contents.
New Lleida buildings as of June 2012: