I find environmental history a great lens to understand cities and their urban development path, to harvest an ecological consciousness.
Understanding natural sites allows to compare and judge the pertinence of urban systems' development as related to the ecology, natural systems and resources management of a city.
A great project which came out in 2009, mannahatta, looks at the origins of New York and its bay and confronts it to today's constructed environment. The project was featured in National Geographics and Van Alen Institute. Here are some snapshots from the interactive application hosted on nationalgeographic.com