A few weeks ago, I went on a Zeppelin cruise over Oakland and San Francisco with some of my Google colleagues. A Zeppelin is a rigid airship and has a frame made of metal alloy. This differentiates it from a blimp, which has no supporting framework. (And then there is a spectrum of semi-rigid airships in between.) Our cruise director described some other features of the Zeppelin that sounded impressive, but I don't remember any of them. The important part is that it hovers slowly at an altitude where you can make out the interesting details of aerial landscapes and building, can see cars, and just make out dots of humans walking around. And because it rides so slowly, you can peak your head out the window and take pictures without the window glare.
On the day we went, San Francisco was doing it's typical overly cloudy thing, so most of my pictures are distorted by huge puffy white pillows down the middle. I still likes the results though (more pictures here).