Visitors to the Three Gorges Dam are reflected in a model replica of Chinaís most controversial engineering project. Like any mega engineering project, there are serious consequences and benefits to weigh up. The stakes don't get any higher than at the Three Gorges Dam, a topic that sharply divides environmentalists, scientists and the government. For years, Beijing has kept public dissent and discussion of the project under control. But a series of geological mishaps and an uncharacteristic warning of impending "environmental catastrophe" in the region reignited the controversy in a major way in 2007. News that another four million residents may be relocated - later explained as a "misunderstanding" - sparked even more unease. But the government moved qickly to douse criticisms of the project, with signs that a deeper and fuller reflection on the impact of the dam won't be conducted publicly for a while. [Sandouping, Nov 30 2007.]