Oscar-winning composer Tan Dun has come up with the theme of his contribution to the 2010 World Expo - a "wind rock" conveying the message of eco protection.

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This was not the first time Tan has used wind as a major element in his music as it also resounded in his score for "Hero," a star-studded hit film directed by Zhang Yimou.

Tan revealed on Friday in Xi'an, Shaanxi Province, that he would take a bolder approach this time. The key message is harmony between nature and humans, he noted.

On Saturday, Tan led the Shanghai Philharmonic Orchestra in Xi'an to stage a concert of "Crouching Tiger, Hidden Dragon," a martial-arts epic directed by Ang Lee.