Oakland is full of historical reminders, some of them enshrined in official registers, others neglected. A century ago, neighborhoods were planned with abundant footpaths and stairways, especially in the old streetcar suburbs within a mile or so of the town of Piedmont. There are roughly a hundred of them there, ranging from small flights of steps to alleyways with their own street signs. That was a time when gravity was respected, if only as a vestigial memory. For our entire previous history as a species, the default method of travel was on foot. The Key System streetcar lines first made the Oakland hills inhabitable by the masses. They ran up the gentle grade of stream valleys, and commuters would walk the rest of the way home to their modest castles. Within a generation, the automobile made this system temporarily obsolete. For the moment, no one walks in the hills, and the city is slowly giving up on the paths, which were once essential infrastructure. They are still useful, though unrecognized, as alternative routes in case of fire or quake.
As I explore Oakland’s geology, I walk by habit and by resolution and as a sign of respect to gravity. Gravity is the key to landscape, and until the rise of mechanical transportation gravity was the prime influence on the layout of cities. Walking helps me view my city with the eye of a geologist at a field site, and I enjoy experiencing Oakland as its 19th-century inhabitants did. And, of course, if I didn’t walk I would be hopelessly out of shape.