How The Chinese Used Ice To Build The Forbidden City

By Simon Griffin on Tuesday, November 19, 2013
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“Just because it’s forbidden doesn’t mean it’s good for you.” —George Hammond

In A Nutshell

The Forbidden City, is one of the largest palaces in the world. It’s a large, sprawling, ancient city, and has baffled historians for centuries as to how it was built. The materials used in its construction were taken from a faraway quarry, and how they got to the city has been a mystery for years. We now know that ice roads were used to transport materials during construction.

The Whole Bushel

The Palace Museum, formerly The Forbidden City, is located in Beijing, China. Beginning in 1406, it took 14 years to build the main part, which went on to house Chinese emperors for almost half a millennium, until 1911, when Emperor Puyi, the last emperor of China, abdicated. But for 491 years, it was the center of Chinese power. As well as being the location for government offices, it housed a total of 24 emperors and their families. Fourteen of these were from the Ming Dynasty, with the other 10 being from the Qing Dynasty.

With a huge moat 52 meters (170 ft) wide, The Forbidden City was so called because it was off limits to the general public. At 74 hectares (183 acres), the city is bigger than the Vatican, the smallest internationally recognized country. Inside the city itself, it is estimated that there are up to 10,000 rooms, although no official survey has ever been done. Its walls are over 8 meters thick and 6 meters tall in places (26 by 20 feet), and these walls completely enclose the city. In short, it required a hell of a lot of materials to build.

As with many ancient structures, its construction lay shrouded in mystery for hundreds of years. Not because of its gargantuan size, but because the materials from which it was built were enormous and extremely heavy. One rock in particular weighed over 300 tons. Adding to the mystery of how these rocks were moved was the fact that they came from about 70 kilometers (43 mi) outside of the city. How people managed to transport such materials over such a long distance stupefied historians and engineers for years. Various theories and methods of transportation were put forward and tested, but none seemed to be a realistic answer. The transport of the time, such as wagons, simply couldn’t have done the job.

Then, a few people from the University of Science and Technology Beijing decided to investigate, and found a document from 500 years ago that solved the mystery. It turned out that the Chinese had decided the safest and most efficient way to transport the materials was to build ice roads between the construction site and the quarries, and move the rocks using sledges. Temperatures in the area would have been cold enough in January to allow such roads to be built and maintained for the 28-day period it took to move the rocks, which were pulled by up to 46 men. Water was applied from periodically placed wells to help the sledges slide along, and the ice was strong enough to withstand the mind-boggling weight of the rocks. With so many similar mysteries of heavy materials transported over great distances, such as the rocks used to build Stonehenge, the answer to this mystery could give insight into others.

Show Me The Proof

Beijing’s Forbidden City Built on Ice Roads
Forbidden City (Palace Museum)