U.S. President Barack Obama arrives at Shanghai Science and Technology Museum to have a dialogue  with Chinese youth in Shanghai, November 16, 2009.[Xinhua]

A general view of the hall where U.S. President Barack Obama is to have a dialogue with Chinese youth at Shanghai Science and Technology Museum in Shanghai, November 16, 2009.Obama arrived in Shanghai Sunday night to start his four-day state visit to China, his first trip to the country since taking office in January.[Xinhua]

A general view of the hall where U.S. President Barack Obama is to have a dialogue with Chinese youth at at Shanghai Science and Technology Museum in Shanghai, November 16, 2009.[Xinhua]