The site is in German and a bit clunky, so follow along: Once the map loads, find a bit you like using the navigation icons (though be aware that you can’t zoom out more than you already are).
When you want to export your view as KML, click on the gray button with a downwards-facing arrow. Choose the default, dargestellter Kartenausschnitt, to export your entire view. (Select Abgrenzung in der Karte angeben to make a selection inside the map, or choose the last option to search for individual landmarks.)
Next, select KMZ as your export format. Voila:
Of course, getting Google to serve Berlin in 3D via the default 3D Buildings layer would be even cooler. As would be textures.
And while we’re on the topic of real estate, check out John Jason Fallow’s latest flight of fancy: In Arizona, property plot polygon heights as a function of their sale value, all linked to the timeline.