Ancient Cave Sheds Light on China's Past

A stalagmite rising from the floor of a cave in China is providing clues to the end of several dynasties in Chinese history.  Slowly built from the minerals in dripping water over 1,810 years, chemicals in the stone tell a tale of strong and weak cycles of the monsoon, the life-giving rains that water crops to feed millions of people.  Dry periods coincided with the demise of the Tang, Yuan and Ming dynasties, researchers report in Friday's edition of the journal Science.

http://dsc.discovery.com/news/2008/11/06/ancient-cave-china.html