UNLIKE the Great Wall, it would not be seen from space. But a 3,700ft Bionic Tower that China's leaders are considering building may come to rival the wall as a feat of human engineering and symbol of national might. Officials in the teeming port city of Shanghai are discussing plans to tackle urban overcrowding by creating a 300-storey home for 100,000 people. Its European designers describe it as a "vertical city".
The concrete, metal and glass tower, costing about £10 billion, would be 140ft higher than Mount Snowdon, the highest peak in Wales, and would contain hotels, offices, cinemas and hospitals.
Dwarfing Kuala Lumpur's twin Petronas Towers, the world's tallest buildings at 1,483ft high, it would be set in a gigantic, wheel-shaped base incorporating shopping malls and car parks.
The Spanish architects envisage 368 lifts, with the journey from bottom to top taking less than two minutes. Water and energy would be transported along 92 vertical columns.
"Of course, we'd all like to live in a house on the beach, but Shanghai's population is expected to reach 30m over the next four to five decades," said Professor Javier Pioz, the head of the team that designed the Bionic Tower. "We need a new way of conquering vertical space."
Pioz has created a root-like system of foundations that would descend 656ft, surrounded by an artificial lake to absorb vibrations caused by any earth tremors. The top of the tower is predicted to oscillate by a maximum of nearly 8ft, as much as the Empire State Building in New York but so slowly that it would not be perceptible to inhabitants.
People would be banned from opening the windows of their apartments, but could breathe fresh air on concourses thanks to openings in the outer glass and aluminium shell.
They would live on 12 levels and although some people would move in as soon as the first level was completed it would be 15 years before the building work above them finally stopped.
The designers have met Xu Kuangdi, the mayor of Shanghai, and urban planners, who have indicated a willingness to proceed and have set up a group to consider possible sites and how to meet the cost from both private and public funds.
Marco Goldschmied, the president of the Royal Institute of British Architects, said the project could herald a much-needed new way of thinking about urban sprawl in China, which is already building the equivalent of 600 cities the size of Bristol. In Shanghai alone 10 new districts are expected to be built over the next five years, each big enough to house 100,000 people.
"If you can send a man to the moon you can certainly build a tower for 100,000 people," said Goldschmied. He hoped the project would form a blueprint for future developments that would help preserve the environment.
However, he added a warning: "The main pitfall is the towering inferno scenario - what happens if fire breaks out? It could be the ultimate disaster. Imagine 100,000 people suffocating. And you'd have to organise the place pretty well to stop people feeling like rats in a cage."