It's China's 'Great Wall' for the 21st century.  The 3 Gorges Dam spans the legendary Yangtze River for 2.3 km (1.4 miles) and is 185 m (over 600 feet) high.  That makes it 5 times bigger than the Hoover Dam.  Construction set a world record, using 16 million cubic m (21 million cubic yards) of concrete. You may know about... read more