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.

Description: a fine, soft, shimmery cloth
Material: long strands of the silkworm's cocoon
First Invented: China, more than 5000 years ago
Characteristics: soft, strong, shimmery; cool in summer and warm in winter
Significance: Silk was a treasured material that sparked trade across Asia.
Cool Fact: The domesticated silk moth (Bombyx mori) is a blind and flightless species that can live only in captivity.

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