Every city has an environmental story, perhaps none so dramatic as Pittsburgh's. Founded in a river valley blessed with enormous resources-three strong waterways, abundant forests, rich seams of coal-the city experienced a century of exploitation and industrialization that degraded and obscured the natural environment to a horrific degree. Pittsburgh came to be known as "the Smoky City," or, as James Parton famously declared in 1866, "hell with the lid taken off."Then came the stor...