BEIJING : China will soon embark on a multi-million dollar project to survey and measure its iconic Great Wall.

Surveillance of the Beijing segment alone will cost US$1.25 million, and teams will start the physically challenging task this month.

It is the only man-made structure that can be seen from space.

At some stretches, the Great Wall of China is even wide enough for four horses to gallop.

And some believe the bricks used for the Wall are enough to build four grand Egyptian pyramids.

Former Chinese leader Chairman Mao even had a saying - "You're not a courageous man until you've been to the Great Wall."

So through the years, this Chinese icon spanning thousands of kilometres has been a magnet for foreigners and locals alike.

Ms Li Chunhong enjoys a view of the Great Wall everyday.

She lives at the foot of a section of the Wall in Beijing's northeastern suburb Huairou.

Ms Li says: "We have climbed many sections of the Great Wall. I hope there will be restoration work so that it will be even better."

Her hopes could be fulfilled soon, with the launch of a multi-million dollar project to survey and measure all stretches of the Great Wall.

The project will not only confirm the actual length of the world wonder, but also provide pictorial data of its overall layout, which is significant to the preservation of the cultural relic.

Up to 10 teams from Beijing who have been training through winter are setting off soon.

It is a challenging and arduous task.

Mr Wang Yuwei, Chief of Beijing Cultural Heritage Protection Department, says: "We will have to walk some days and rest in between. We are also limited by the weather. There are no proper paths and some paths are covered with wild grasses. So this year, we can only trek in the months of April and May, and again from November to December."

On segments deemed too dangerous for humans to trek, Global Positioning Satellite (GPS) will be used.

GPS is more precise than surveillance by humans, but it is a costly technology that will be employed selectively.

A temporary order stipulates that areas within 500 metres of the Great Wall are to be protected.

Mr Wang says: "The Beijing section of the Great Wall is more than 600 kilometres long but some parts have not been surveyed, for instance, these "mini castles". We will not only have to trek along the Great Wall but also travel to these areas."

And within two years, new laws are expected to better preserve this treasured legacy.