Some major cities around the world have full 3D imagery that you can view up close in Maps. To access it, first switch to the Satellite view by tapping the ‘i‘ button and choosing that option.
Tap the map to bring it full screen again, and zoom in on a major city, such as London, New York, or Paris. When you get close enough slide up on the screen with two fingers to change the viewing angle. You’ll notice the buildings now appear in 3D.
You can pan around by dragging your finger, pinch to zoom, and use two fingers to rotate the view. To return to the standard plan view press the 2D button in the top right.