While serving as an administrator for [[Hangzhou]], the poet [[Su Shi]] (1037-1101) had a large pedestrian [[causeway]] built across the [[West Lake]], which still bears his name: Sudi (蘇堤). In 1221, the [[Taoism|Taoist]] traveler Qiu Changchun visited [[Genghis Khan]] in [[Samarkand]], describing various Chinese bridges encountered on the way there through the [[Tian Shan]] Mountains, east of [[Yining City|Yining]]. The historian Joseph Needham quotes him as saying: