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"Things aren't looking good for Shanghai, either. Located on China's coast, this sprawling city was built on swamplands surrounding the mouth of the Yangze River. Originally a small fishing village, Shanghai began to draw more and more residents in the mid-19th century. Modest homes were replaced by breathtaking skyscrapers (not to mention some of the best shopping venues in Asia), and Shanghai soon became the most densely populated city in the world, housing over 20 million people by 2001. The city was handling rapid expansion just fine until the early 20th century, when wells became a major source of water and the underlying sediment deposit was disturbed. According to PBS, Shanghai sank roughly eight feet between 1921 and 1965, which equals about two inches per year. The city still continues to drop at a rate of about half an inch per year.
According to experts, not much can be done to keep Shanghai above ground — the city is simply too heavy for its foundation. However, in an effort to slow the sinking process, all new high-rise buildings must be built with deep concrete piles to help support their weight. If you have any interest in seeing the architecture for which Shanghai is both famous and floundering, don't wait too long."
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