Adil Yoltay writes in about CitySurf, a free 3D viewer from Turkey:
We are 3 developers have started 2 years ago CitySurf Project and it will be finished nearly. CitySurf free OpenGL-based viewer, which connects to servers for streaming of content, elevation, imagery, road outlines, 3D buildings, points of interest, etc. (like google Earth and Microsoft Virtual Earth concepts but faster then others).
A Youtube video of the app in action is quite impressive, showing plenty of textured 3D models:
They presented at Cebit 2006 Istanbul, and made it to Turkish CNN — video snippet here.
You can download the application, and I gave it a quick run. Everything is in Turkish, but you can easily guess which buttons do what. The interface looks a lot like Google Earth or ArcGIS Explorer, with layers for points of interest located in Turkish cities. Labels and roads are vector-based (nice), navigation is snappy, and some of the 3D buildings have very high resolution textures — the highest I’ve seen in a 3D viewer. This is put to good use in a few streets to allow actual window shopping, though I’m not sure how well this would scale. Finally, CitySurf isn’t an actual virtual globe (i.e., a sphere), but a viewer for rendering a specific area of terrain.