Now China's Bureau of Cultural Relics has announced plans to restore a five-kilometre stretch in the mountains of Inner Mongolia.

The Great Wall of China

6,500 km long 3.5 metres high 4.5 metres wide Completed in 221 BC Took 10 years to build

The bureau has allocated 600,000 yuan ($72,290) to make the repairs and says that the project is the first effort to renovate larger portions of the Great Wall.

Work is expected to take at least five years, after which the ancient monument will be open to tourists. It is planned that 1,000 metres of the wall will be repaired each year.

The wall will be restored to its original appearance using rocks from mountains.

However, limited funds and lack of equipment means that many sections will not be renovated.

Astonishing monument

The Great Wall is said to be the only manmade object visible from space.

The Great Wall of China stretches 6,500 km

From its starting point on the coast north of Beijing, the wall rolls an astonishing 6,500 km across mountains and deserts until it finally peters out in the country's arid far west.

When first built more than 2,000 years ago, it stood more than 3.5 metres high, 4.1 metres wide on the bottom and 1.5 metres wide at the top.

It required hundreds of thousands of workers and took 10 years to complete.

Most of the famous stretches of the wall visited by tourists were actually built much later, during the Ming (1368-1644) and Qing (1644-1911) dynasties.

Many stretches of the wall were extensively repaired under the Ming and Quing, and are in better condition.

The older wall was built by the Qin dynasty, after it united China in 221 BC. It runs further north across the wild mountains that form the southern edge of the Mongolian step.

Exposure to harsh weather conditions over centuries has left it in a dilapidated state, officials said.

Originally launched last year, the project stalled because of lack of funds. Only 300 metres of the section have been renovated so far.