An ancient man-made near ground surface rock cavern group was found in Longyou County, Zhejiang Province. The 24 large caverns were excavated 2000 years ago.
浙江省西部龙游县的龙游大型古地下洞室群由24个洞室组成，该洞室群开挖于2000年前。
2
A structure usually refers to any large, man-made object permanently fixed to Earth's surface or in its orbit, as a result of construction.
结构通常指固定于地球表面或绕地球轨道运行的大型人造建筑物体。
3
For natural, man-made stone craft and refurbishment of the crystal surface, suitable for mining, hotels, Buildings, supermarkets, hospitals, schools and so on.