Every second, 32,000 cubic feet of water rushes over a horseshoe-shaped basalt ledge, churning up a dome of mist and white noise that enfolds the entire 1,500-foot-long, four-story-high shelf. Willamette Falls, the West’s biggest waterfall, is surpassed in the U.S. only by Niagara. It would astound anyone who saw it — if they could see it. But for a century now, industrial structures have blocked access to this natural wonder.