Section of China's Great Wall resurfaces after four decades

A section of China's Great Wall, submerged in a reservoir in north of Hebei Province for nearly four decades, resurfaced following decrease in water levels.

The section of the Great Wall, in Kuancheng Man Autonomous County, was built more than 500 years ago during the Ming Dynasty.

It served as an important pass to the northern and northeastern frontiers.

A massive reservoir was built in the region in 1975.

The section of the wall was eventually submerged as the water level rose.

The reservoir has been depleted as agricultural and industrial activity have increased downstream.

The Great Wall, listed as one of the seven wonders of the world, has a total length of 21,196 kilometres.

It was damaged and sections had disappeared in a number of places, while it was well preserved as a major tourist attraction in Beijing.

The Great Wall was built continuously from the third century BC till the 17th century AD to defend China from external attacks.

It was listed as a World Heritage Site by UNESCO in 1987.

Over four million tourists visit the Great Wall every year as it is the centre of China's tourism campaign.

Each tourist pays about $17 to visit it in different places, especially in Beijing.