冷沙漠边缘 · COLD DESERT EDGE
Not All Deserts Are Sand Seas — Mongolia–China · Gobi Desert
戈壁横跨蒙古与中国北部，面积约 130 万平方公里。它许多地方不是沙海，而是砾石、草原与裸岩，是游牧机动与绿洲定居之间的雨影边疆。
戈壁对农田苛刻，却不必然阻止移动。辽阔空间更适合商队、牧群与军道——它们比固定田地更能承受距离。
The Gobi covers about 1.3 million km² across Mongolia and northern China. Much of it is gravel, steppe and bare rock, a rain-shadow frontier between pastoral mobility and settled oases.
The Gobi is a hard map for farmers but not for movement. Its wide spaces favored caravans, herds and military routes that could handle distance better than fixed fields could.