Bettina Johae's Edges.
Bettina, mostly on bicycle, traced the edges of New York's five boroughs with her camera in tow. The amazing results, a chronicle of edges, can be viewed here. The website introduction offers a beautiful demonstration of her diligence: red dots quickly fill in the edges of Brooklyn, Staten Island, Manhattan, Queens, and the Bronx indicating where each of her photos was taken.
Want to see more? Bettina is offering tours of the different boroughs on bicycle. For more information, email her at firstname.lastname@example.org.