In Chinese,
四大无人区 ('the four great no man's lands') refers to four uninhabited high-altitude wilderness areas in northwestern China:
可可西里 (Hoh Xil),
羌塘 (Qiangtang),
阿尔金 (Altun) and
罗布泊 (Lop Nur). Also used in war/conflict contexts as 'no man's land' between front lines.
