MICHAEL ZHANG, PETAPIXEL:
"Picsbuffet is a new visual image browsing system that lets you explore and search millions of photographs through an interface that feels like Google Maps.
"Developed by researchers HTW Berlin, the service groups photo search results into multiple layers. The highest level is least specific, and it contains all kinds of photos about all kinds of subjects. As you zoom in to a particular photo, the photos on each level are more and more similar to the photo you’re zooming into.
"Clicking on a photo enlarges it and gives you a link to the source where it was found. A heat map in the upper left corner of the screen shows you other areas of the layer where there may be relevant and interesting photos."
Read more, and see how it's done, here.