In general, the railroads had a positive impact on the relationship between eastern cities and the Great Plains, since they allowed for the transportation of people and goods between these two areas in ways that were far quicker and more efficient than before.
The Great Wall of China's history began in the Spring and Autumn Period (770–476 BC), was first completed in the Qin Dynasty (221–206 BC), and was last rebuilt as a defense in the Ming Dynasty (1368–1644).
