Underwater world

In Fuling, in Southwest China's Chongqing, Baiheliang Underwater Museum, the first of its kind in the world, shows how the Chinese made use of water resources.

About 1,300 years ago, the ancient Chinese would gather at Baiheliang, or the White Crane Ridge, in the upper reaches of the Yangtze River when it protruded from the water during the dry season, usually from December until March.

Then they picnicked, flew kites and played games on this 1,600-meter-long natural ridge which averages 15 meters in width.

This place got its name because white cranes would flock to the place. But local people also believed that a Taoist, who meditated on the ridge and finally became immortal, transformed into a crane and flew away.

The regular exposure of the stone ridge also provided the ancient people with the chance to observe and record water levels.

So, on the huge rock there are 18 sculptures of fish that serve as water-level markers and record 1,200 years of changes in the Yangtze's water levels.

There are also more than 30,000 Chinese characters carved into the rock there, and the area is listed as one of four State-level national treasures in the Yangtze River's Three Gorges area.

The ridge is believed to be the world's most ancient hydrographic survey station.

Due to the Three Gorges Dam project, the huge rock was submerged in 2001. So, a special museum was built to preserve its history.