What did our cities' natural landscapes originally look like? In a sprawling metropolis such as Tokyo, with concrete encrusting almost every inch of earth, walling every riverbank and towering up to the skies, it is almost impossible to imagine.

Leaning over the railing on the top deck of a five-story ferry, I watch the southern most tips of the two peninsulas that border Tokyo Bay fade into the distance of the gray-blue sea. The gargantuan vessel rocks gently beneath my feet, the steady ...