Envisioned and created by Cassidy Curtis (and a few photographer friends), this site is a "study of graffiti-covered walls as they change over time" in San Francisco. While reviled by public officials and city sanitation workers, these walls seem to come alive with a flourish, as visitors can watch these locales change over time. Currently visitors can browse through five different locations in the city. The real star of the site is the graphical interface that allows visitors to zoom in and out through the different phases of each site's respective artistic evolution. Along with this fun feature, visitors can look at each site during various transformations, giving one a sense of how each wall has been changed by a number of graffiti artists.