I know earlier sections used less sophisticated techniques than later when engineering technology grew. This might be the areas of more or less packed Earth.
BEIJING (Reuters) - Sand storms in northwest China are reducing sections of Great Wall to mounds of dirt and may cause them to disappear in about 20 years, state media said on Wednesday.
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BEIJING (Reuters) - Sand storms in northwest China are reducing sections of Great Wall to mounds of dirt and may cause them to disappear in about 20 years, state media said on Wednesday.
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