Girls' coming-of-age in SW China's black-teeth tribe

At the age of 15, girls in China's Huayao Dai ethnic minority group go to the forest, pick a certain kind of fruit, put it into their mouths and start to chew.

The black sap of the Chinese fevervine fruit darkens their teeth. The process is repeated over and over again until the dye becomes permanent.

This special coming-of-age ceremony has been performed for thousands of years by the people living in Jiasa Town in southwest China's Yunnan Province.

The Huayao Dai people are one of the oldest ethnic groups in Chinese history. They even had their own kingdom in southwest China that lasted about 170 years until 109 B.C.

Today, the Huayao Dai people, as descendants of the ancient nature-worshiping kingdom, still live a secluded and traditional life. The men farm in the fields, and the women weave textiles at home.

Until the 20th century, women there considered their teeth beautiful and the men's undyed white teeth eccentric. 

The tradition is reported to have health benefits for teeth.