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FILE - In this Friday, April 20, 2012 file photo, a fish robot swims at the Marine Robot Pavilion of the EXPO 2012 in Yeosu, South Korea. The Expo 2012 will open for three months on May 12 in Yeosu with a theme focused on the ocean. Its formal theme is "The Living Ocean and Coast: Diversity of Resources and Sustainable Activities." (AP Photo/Ahn Young-joon, File)

Expo 2012: South Korea

Expo 2012 has opened in South Korea's coastal city of Yeosu for a three-month run. The fair, which kicked off Saturday, May 12, has the largest number of robots in the history of expos, including a robot fish that explores underwater resources in an environment-friendly way.