Children gather before the camera at an elementary school in Qamdo, southwest China's Tibet Autonomous Region, March 10, 2009. Qamdo is home to 620,000 people of 21 ethnic groups and boasts historical sites dating back to as far as 4,000 years. (Xinhua/Purbu Zhaxi)

Picture taken on March 13, 2009 shows a general view of Qamdo, southwest China's Tibet Autonomous Region. Qamdo is home to 620,000 people of 21 ethnic groups and boasts historical sites dating back to as far as 4,000 years. (Xinhua/Purbu Zhaxi)

A woman buys vegetable at a market in Qamdo, southwest China's Tibet Autonomous Region, March 11, 2009. Qamdo is home to 620,000 people of 21 ethnic groups and boasts historical sites dating back to as far as 4,000 years. (Xinhua/Purbu Zhaxi)

Picture taken on March 14, 2009 shows a view of a characteristic street in Qamdo, southwest China's Tibet Autonomous Region. Qamdo is home to 620,000 people of 21 ethnic groups and boasts historical sites dating back to as far as 4,000 years. (Xinhua/Purbu Zhaxi)

Picture taken on March 15, 2009 shows a general view of Qamdo, southwest China's Tibet Autonomous Region. Qamdo is home to 620,000 people of 21 ethnic groups and boasts historical sites dating back to as far as 4,000 years. (Xinhua/Purbu Zhaxi)