AT FIRST GLANCE, Spokane, Washington, population 200,000, strikes one as the embodiment of a gritty industrial city past its prime. Hard up against the Idaho border, Spokane’s glory came in 1974, when it hosted the World’s Fair. Building the site for Expo 74 required a massive makeover of the city core, one that saw its rail yards, parking lots, and warehouses turned into a charming waterfront park bisected by the Spokane River. But as a result, the city was confronted with mounds of concrete that had been ripped up from the industrial downtown to create the park.
About two miles from the Expo site runs a long, steep bluff, the east side of a wide valley gouged out by ice age floods twelve thousand years ago. According to local lore,…