Duluth clings to a rocky hillside where clusters of houses nestle amid broad expanses of woods and meadows and where cascading streams tumble toward the vast waters of Lake Superior. Duluthians, most of whom are but a few minutes walk from a forest trail or a creek-side overlook, treaure the green space that was preserved for future generations by early city planners. In these images, Craig and Nadine Blacklock have captured the essence of...