Why it looks like this

Mountains press Lanzhou against the Yellow River from both sides, so the city grew the only way it could: lengthwise. The main streets, the railway and the river all run in parallel down a corridor sometimes only two or three kilometres wide.

The city has guarded this crossing since the Silk Road era, but the river was crossed by ferry and by seasonal bridges of boats until 1909, when the Zhongshan iron bridge — built with German parts hauled overland — became the first permanent bridge over the Yellow River anywhere on its course.