which settlements was built at a very high elevation becuase it was close to the silver mines of cerro rico in

Answer 1

http://www.unesco.org/courier/2000_03/uk/dici/txt1.htm

Potosi, Bolivia. It was a rich city in the 16th to the 18th centuries, when the silver mines were going strong and silver was being sent back to Spain. Today it is not prosperous.
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