Here's a satellite photo of San Francisco, courtesy of Google Maps.
On the lower half of the picture, you see the south face of the buildings as expected. But above the center line, you see the north face of City Hall, the Federal Building, etc. It's like the map is actually two photos taken from different angles (above the equator & north pole?) and then spliced together.
At first I thought is was an optical illusion, but the more I look at it the more I think something's fishy here.