秦始皇曾修筑一条世上最早、最长也最宽的超级马路——军事直道。这是秦始皇为快速集结调动军队和运输粮草物资而建的，是可与长城媲美的边防军事设施。这条军事直道，全长900公里，北起九原即今内蒙古包头市西北，南至云阳即今陕西淳化西北，横穿陕甘两省14个县。长城外路面宽 Qin Shihuang had built one of the earliest, longest and widest super-roads in the world - the military straight road. This was built by the Qin Shi Huang for quickly mobilizing the army and transporting forage materials and is a frontier defense military facility comparable to the Great Wall. This military straight road, a total length of 900 kilometers, starts nine times in the north, northwest of Baotou City, Inner Mongolia in the north, and now runs northwest of Yunhua in Shaanxi Chunhua, crossing 14 counties in Shaanxi and Gansu provinces. The Great Wall outside the road wide