Blue Marble

One of the default pictures included with the iPhone is a beautiful image of the Earth as seen from space. Unless you weren't paying attention, you saw this picture when you first purchased your iPhone, and you can still view it by going to Settings --> Wallpaper --> Wallpaper; it is the second image provided by Apple. Here is what it looks like as a wallpaper on an iPhone.

If you have ever wondered where this photograph came from, a recent post from Gizmodo sheds some light on the subject, although to get the full story you need to go to some more sources, including this page from the Swiss Institute for Atmospheric and Climate Science. Here is a short version.