What is this article mainly about? ACHIEVE A REALLY GREAT WALL PLEASE HELPP EASY
A. A mapping endeavor of the Great Wall of China is slated to continue for another year.
B. Sandstorms that have plagued China for years have resulted in the loss of part of the Great Wall.
C. A mapping endeavor has yielded the discovery of new sections of the Great Wall, which is longer than previously thought.
D.Chinese officials anticipate measuring older parts of the Great Wall during an ongoing mapping project.
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BEIJING, China (Achieve3000, May 5, 2009). The Great Wall of China is greater than anyone realized. Government officials have uncovered previously undiscovered sections of the ancient Chinese monument that total about 180 miles (290 kilometers) in length.
The discovery is the result of a two-year government study in which officials used mapping technologies such as GPS devices to determine if parts of the wall were concealed. They found that hills, trenches, and rivers had indeed been covering up portions that stretch from Hu Mountain in northern Liaoning province to Jiayu Pass in western Gansu province.
It's an important discovery, since the Great Wall is the most renowned monument in China. Chinese emperors built the fortification, which spans at least 3,900 miles (about 6,275 kilometers) with the newly discovered sections, across the northern part of the country in an attempt to protect China from Mongols and other invaders from the north. The wall was constructed in numerous sections over several centuries, beginning in the 3rd century BCE. The oldest sections of the walls are believed to have crumbled-all visible sections were built during the Ming Dynasty (1368 to 1644).
The newly mapped parts of the wall were also built during this period, but had been submerged over time by sandstorms that moved across the arid region, the study said.
Sandstorms continue to threaten the fortitude of the Great Wall. Chinese archaeologists say that the storms are reducing portions of the wall in Gansu province to "mounds of dirt" that may disappear entirely within 20 years. Why? One reason is that portions of the wall in Gansu were constructed of packed earth, which proved less impervious to storms than the brick and stone used in much of the wall's construction. For the most part, though, the archaeologists blame a farming method that took hold in the 1950s and involved irrigating the land in order to increase crop production. Over time, this method depleted much of the land of its water and caused it to become a desert. The proliferating miles of desert are causing the sandstorms that have always plagued China to become more intense.
Tourists also threaten the continued survival of the wall, several sections of which draw hundreds of thousands of visitors each year, including the most popular location at Badaling, just north of Beijing. In that area, almost every brick has been carved with people's names or other graffiti. Commercial development, meant to accommodate the tourists, has also contributed to the crumbling of the wall.
In the last few decades, China has been restoring parts of the wall, as well as trying to rein in commercial development on and around it.
The mapping study, a joint project conducted by the State Administration of Cultural Heritage and State Bureau of Surveying and Mapping, has another year to go. During this time, officials will map sections of the wall built during the Qin Dynasty (221 BCE to 206 BCE) and the Han Dynasty (206 BCE to 9 BCE).
