According to a press release last week, Hamburg is to become the first European city to be completely available in 3D via Google Earth. See: Hamburg in 3D at Google Earth (PDF).
As was posted to TT earlier, 3D models of specific landmarks are already available throughout Germany.
The plans for Hamburg go much further than this, however.
CyberCity AG, in cooperation with the State Office for Geo-Information and Survey (LGV) of the city of Hamburg, is planning to make the entire city available in 3D. The imagery will be photo-realistic, as opposed to the current "Sketchup" models that can be seen in Google Earth.
It hasn't been announced exactly when this will become available. But presumably it will be within the next few weeks.
There are already 3D maps of Berlin and Munich available via DVD. These software packages, however, are not "Internet-aware" and "Web 2.0" like Google Earth is.
Hamburg 3D in Google Earth
