Of the Yellow River Iron Bridge located at Baita mountain north of the city of Lanzhou, gold Chengguan ago, \ x22 world of the Yellow River first bridge \ x22 called, is one of the landmark in the city of Lanzhou. Before the completion of Iron Bridge, where there pontoon bridge across the Yellow River. Pontoon bridge built in the Ming Hongwu years before (AD 1368-1398), named Chen-yuan bridge, this remaining pillar on a bridge used by up to three meters and weighing about a few tons, there \ x22 Hongwu 9 Year \ x22 words.