Demolition of the last cofferdam protecting the just-completed main wall of the Three Gorges Dam, the world's largest, started at 4:00 on Tuesday afternoon in the middle reaches of the Yangtze River, China's longest, with explosives enough to topple down 400 10-storey buildings.

The operation took about 12 seconds, causing nearly 190,000 cubic meters of concrete fragments from the upper-30-meter section of the cofferdam to tumble into the river.

The removal of the cofferdam means the main wall of the Three Gorges Project will formally begin its role in flood control, which will be two years ahead of the schedule.

The world's largest dam in Three Gorges area, central China's Hubei Province, was completed on May 20, signifying a milestone accomplishment of major structure of the mammoth Three Gorges water control project that aims to tame the flood-prone Yangtze River.

Source: Xinhua