Work crews Thursday begin dismantling the two dams on the Elwha River, on Washington's Olympic Peninsula. By some measures, this is the largest dam-removal project ever — and, at 210 feet, one of the dams is certainly the tallest dam ever taken down. The process is an extremely tricky one — in terms of engineering, ecology and politics — but environmentalists hope this project heralds the beginning of the end of the age of big dams in the American West. Those who like big dams, for economic reasons, worry about the same thing. Michele Norris talks with NPR's Martin Kaste.