PHOTOS: TOP LEFT: ANTHONY DURNIAK; TOP RIGHT AND BOTTOM: LIU CHAN/XINHUA/AP PHOTO

On 6 June, the last cofferdam—a temporary structure standing between the waters of China’s mighty Yangtze River and the main wall of the Three Gorges Dam—was blown up in a series of blasts detonated over a 12‑second period [photos, middle and right]. The 2.5-kilometer-wide dam, by far the world’s largest, now holds back the full force of the river and is ready to ramp up to its total rated electrical capacity of 22 400 megawatts. In the generator room on the dam’s left bank [left] are caps of the fourteen 700‑MW turbines now in operation. They were manufactured by a consortium of six Western companies. Another 18 turbines, of Chinese manufacture, are being installed in a similar room on the dam’s right bank.

Because of their far-reaching environmental, social, and economic ramifications, all big dams are controversial. But Three Gorges has been probably the most controversial ever. It divided the political leadership of this one-party state and prompted a muckraking author, born into the Communist elite, to write an eloquent denunciation. Now only time will tell whether the dam will fulfill its prodigious promise or whether some of the naysaying about social and environmental effects will turn out to have been well founded.