Walking is unique to the human species and fundamental to its evolution, yet after four million years as a superbly successful adaptive strategy, walking has, within a century, become endangered. How did we get here, and where are we going next? The author examines the ecology of walking in the urban and suburban United States through seven vignettes that explore the intersection of walking with urban form, history, consumerism, public health, civil liberties, the arts and spirituality. (a) For the covering entry of this conference, please see ITRD abstract no. E204599.