Great Wall of China ‘Even Longer’

A new mapping study shows that the great wall is longer than was previously thought. From the BBC:

A two-year government mapping study found that the wall spans 8,850km (5,500 miles) – until now, the length was commonly put at about 5,000km.

Previous estimates of its length were mainly based on historical records.

Infra-red and GPS technologies helped locate some areas concealed over time by sandstorms, state media said.