Google has had a busy week. Not only did they release Google Earth version 5.1 and then release new imagery for many parts of the world, but today they added two more cities in 3D: Copenhagen, Denmark and Marseilles, France.
The addition of Copenhagen is very timely, as Google just recently released some tools in preparation for the COP15 climate change conference in Copenhagen. Oddly, though, the building that will house the conference (the Bella Center) was a bit too far away from downtown to get modeled.
To view these or any other 3D buildings, make sure you turn on the 3D Buildings layer inside of Google Earth.