Mao Zedong once said: ‘He who has not climbed the Great Wall is not a true man.’ I wonder what China’s chairman would have thought of this correspondent, given that I was recently in China, but never went within cooee of the Great Wall.

My excuse could be that there is far more than one Great Wall, so where does one start? And it is a rather large country.

Correcting the myths and legends, such as there being only one Great Wall in China, and that you can see it from space (you can’t), is a strong theme in China’s Great Wall, written and directed by Christian Twente.

The documentary filmed by German ZDF television and National Geographic, contains interviews, historical recreations and the stunning cinematography. The breathtaking scenery, I might add, has finally bestirred me to replace the old Kmart Magnavox with something approaching today’s television technology.

China’s great wall or walls were built and rebuilt between the 5th century BC and the 16th century to protect the Middle Kingdom from invading barbarian hordes to the north.

The first major wall was built during the reign of the first emperor in the Qin dynasty, created by the joining of several regional walls and located much further north than the current and last Great Wall.

The documentary tells us that almost every dynasty built its own wall, or at least sections of it. Some of them are hardly walls at all, but rather earthwork mounds or even defensive ditches.

The Great Wall of China that most of us visualise today is a relatively modern structure constructed during the Ming dynasty in the 16th century. As the programme says, no-one really knows how old the walls are exactly, or exactly how long.

But since the making of the television programme, the Chinese Government in April 2009 announced that the Great Wall was even greater than previously thought. A two-year government mapping study discovered that the Great Wall spans 8,850km - until now, the length was commonly put at about 5,000km.

Previous estimates of the barrier’s length were based mainly on historical records. But infra-red and GPS technologies helped locate some areas concealed over time by sandstorms, according to state media.

Lonely Planet on China tells us that an easy way to view today’s Great Wall is to take the well pounded path to Badaling, about 70 kilometres northwest of Beijing. But beware the tourist hazards;"unless you visit during the bitterly cold days of winter, don’t anticipate one-to one with the wall and prepare for guard rails, a carnival of souvenir stalls and squads of tourists surging over the ramparts."

So better to avoid weekends and holidays or try somewhere more remote, like Huanghua, 60km north of Beijing, where the visitors are fewer and the wall is managed by local villagers, not the tourist authorities.

The entrance fee is a paltry two yuan. Be prepared for a wild wall including a stiff climb up a hillside before going through a gap in the wall into the crumbling ramparts... if you head north, you can’t miss it.

Lonely Planet isn’t the first to complain. "Crudely rebuilt in places to resemble a Disneyland attraction, but mostly left to crumble unattended," wrote Peter Ford in the Christian Science Monitor.

But there is good news with the introduction of new wall laws. From late 2006 it became officially illegal to remove bricks or stones from the Great Wall, to drive vehicles along it, to hold all-night rave parties on it, build houses right up against it or apply a splash of graffiti, as many had been doing. 

And the research work is going on. The study to uncover more of the structures is continuing in order to map sections of the wall built during the Qin (221-206BC) and Han (206BC-9AD) dynasties.

This business of discovering and protecting the Great Wall is something relatively new for the Chinese. Some conservationists within China are sceptical, but these are steps in the right direction.