David Kestenbaum

The Stradivarius violin gets its name from master craftsman Antonio Stradivari. When he died in 1737, his secrets died with him: No one has ever been able to duplicate the sound of the violins or violas he made.

His instruments have taken on a mythical quality. Today they fetch millions of dollars at auctions; Sotheby's will soon auction off a viola that it expects to sell for $45 million.

China's central bank is sitting on a giant pool of U.S. dollars. It's the world's biggest holder of foreign reserves, worth over $3 trillion at last count.

All that money has piled up because every year, China exports more than it imports; it runs a trade surplus.

There are lots of reasons for China's trade surplus. In the past few decades, China has built an amazing manufacturing ecosystem. It's become the factory to the world.