How did you make this?

Each layer is made of one or more photos, stitched together to create a seamless image of a wall. To do this, I align all of the photos to correct for changes in perspective, and do color correction as needed. I've been doing this using Adobe Photoshop, with a plugin to fix problems like barrel lens distortion. The interactive explorer tool was built using Macromedia Flash MX, with the help of my friend Eric Rodenbeck at Stamen Design.

Why are the outlines such strange shapes?

If a photo is shot from an angle, it must be stretched out into a trapezoid to correct the perspective and flatten the wall. Also, if there's something in the way of the camera, I might edit that out, which leaves irregular holes in the outline.

Why are some layers all chunky and blurry, but not others?

The photos come from many different sources: different types of film, digital cameras, images found on the web. If the source material is underlit, low-res, or compressed, then the film grain, big pixels and jpeg chunks will show up in the finished collage.

Are you a real archaeologist? Do you write graffiti?

No. I'm just a guy who takes pictures and stitches them together. I do not have a degree in Archaeology. I don't write or paint on walls, just in my sketchbook. When I named this site, I was really just being cute.

Where exactly are these walls? Why are there no maps?