A general view from the Huangpu River shows the Chinese Pavilion at the Shanghai 2010 Expo site in Shanghai August 5, 2009.[Agencies]

Migrant construction workers are seen in the Shanghai 2010 Expo site in Shanghai August 5, 2009.[Agencies]

 A migrant construction worker carries his tools as he walks near the African area in the Shanghai 2010 Expo site in Shanghai August 5, 2009.[Agencies]

Migrant construction workers walk up the stairs into the Chinese Pavilion at the Shanghai 2010 Expo in Shanghai August 5, 2009. [Agencies]

A migrant construction worker walks with his tools under the Chinese Pavilion at the Shanghai 2010 Expo in Shanghai August 5, 2009. [Agencies]

A migrant construction worker walks near the African area at the Shanghai 2010 Expo site in Shanghai August 5, 2009.

Migrant construction workers push away muddy water from an interior at the Chinese Pavilion at the Shanghai 2010 Expo in Shanghai August 5, 2009.