Earth Island Journal - The dam industry has choked more than half of the Earth's major rivers with large dams. The consequences of this massive engineering program have been devastating. The world's large dams have wiped out species, flooded huge areas of wetlands, forests and farmlands, and displaced tens of millions of people. While not every dam causes serious problems, cumulatively the world's large dams have replumbed rivers in a massive experiment that has left the planet's freshwaters in worse shape than any other major ecosystem type, including tropical rainforests. Despite this, large dams are back in style. Several massive projects are being proposed on rivers across the world, from the Amazon to the Mekong and the Nile and even on rivers in the high reaches of the Himalayas. Here are 10 things you should know about dams and their impact.