Silk is the finest, most luxurious cloth in the world. It is soft and shimmery, yet strong and sturdy. Long ago, silk making was also one of the world's most treasured secrets. The Chinese invented silk almost 5,000 years ago. They traded silk with far- away countries, but would not reveal the source of the precious material: the strands of a silkworm's cocoon. For thousands of years, this secret brought wealth and power to Chinese empires.

Image credits: main image, © AMNH/D.Finnin.