The weather was clear and warm in mid-August, an ideal time for exploration.

Two hours of comfortable travel westward by bus from Shanghai brought me and my Chinese guide close to the outskirts of the little town of Jinze. Upon leaving the bus, we were at a loss to discover how to travel the remaining few miles in search of the newly constructed Rainbow Bridge, recently featured on America's PBS-TV (Secrets of Lost Empires II, a production of WGBH, Boston).

The few people we met had no suggestions on how we might reach Jinze and had never heard of the bridge. My attempts at hitchhiking, an uncommon activity in China, were ignored by the few passing cars and trucks. After an hour, however, a taxi stopped and took us aboard. It was fortuitous: the driver had just relocated his brother from their home in Shanghai to a new job in the countryside. He was pleased to take us to Jinze to find the bridge he had never heard of.

China led the world in the building of bridges just as it led in other fields—printing, gunpowder, the compass, and the invention of paper money. These inventions go back a thousand years to the Song Dynasty and all of them served to unite the Chinese people.

Suspension bridges using iron chains preceded their counterparts in the West by a thousand years. The visitor to Nanjing today will see a great modern suspension bridge over the Yangtze River, uniting the countryside with the metropolis. Years ahead of the Romans, the Chinese developed the long, low, shallow arch for the stone bridge, in contrast to the higher, less efficient, more nearly semi-circular Roman arch. Hundreds of years ahead of the rest of the world, Chinese engineers built a stone bridge in Fujian province that remains, perhaps, the longest stone bridge in the world, nearly a mile-and-a-half in length.

But until last year the only arched bridge made of straight timbers, the Rainbow Bridge, existed only in a painting done nine hundred years ago.

For those who live on their shores, rivers are divisive until bridged. This land is fraught with rivers and canals. The two principal rivers are the Yellow River and the Yangtze, flowing generally from west to east. To promote commerce, the authorities built many canals drawing water from these rivers, most notably the Grand Canal uniting Beijing in the north with Hangzhou farther south and passing through the bustling cities of Yangzhou and Suzhou. While shipping was vastly promoted—the bridges having great arches to permit navigation—until the bridges were built, those who lived along the shores were greatly inconvenienced by the separation from their neighbors.

It is the stimulus of this threatened divisiveness that led to the unmatched achievements of the bridge-builders. But, over the narrow canals, how much cheaper and more efficient if, instead of huge, heavy blocks of stone, bridges could be built of lighter material like wood that is more easily and quickly shaped. So, nine hundred years ago there appeared the Rainbow Bridge, so named because of its shape and colors.

We had promised our taxi driver 250 yuan, about $30, for the ride to the bridge in Jinze and the return to Shanghai where he had to go anyway. Perhaps that is why he was gracious in questioning residents of the town on the whereabouts of the bridge. Yet no one seemed to know where it was, although we were misdirected to several of the many stone bridges along the canal. At last, two little boys provided the location and we soon beheld the only bridge of its kind in the world. It was built by local people who were directed by Professor Tang, a Chinese student of bridge architecture, Professor Barbash from MIT, and other American and Chinese experts.

Because the bridge had been featured on American television, we had expected a crowd of tourists. We were surprised to find ourselves the only visitors.

The canal is just forty feet wide at the site selected and, because dwellings were close to the banks, there was no possibility of prefabricating a bridge on shore and moving it into position.

Among the challenges in construction was the use of straight timbers to form a curved arch, while restricting the technology to what was available nine hundred years ago. This entailed the use of heavy bamboo ropes, rarely seen today, and special antique nails to bind the timbers together. It also necessitated anchoring two small boats in mid-stream so that men could work on the underside of the structure. Many calculations and model replicas, deduced from the old painting, were also essential to the tasks at hand.

The picture of the completed Rainbow Bridge (above) shows the excellence of this new creation. A first step was building sections of three timbers, each having one rising from each bank and a third lying horizontally atop them. These sections were then interlaced with four-section timbers. Sturdy, woven bamboo rope and a few nails bound the sections together. As depicted in the photograph, steps and ornate railings were added to the frame to form the beautiful, finished bridge.

We purchased the picture at a tiny shop run by an old woman whose house was headquarters for the engineers and riggers. The Chinese characters for Rainbow Bridge appear at top left where the Romanized pinyin for rainbow is printed as Pu qing (Poo ching).

The waterways and the bridges that span them have served to unite the people of China and to allow the exchange of regional cultures. The Rainbow Bridge has further united contemporary China with its brilliant past. And all of this melding has now been joined with American culture and science for the betterment of relations between two of the world's greatest countries.