The Great Wall of China is considered to be the only man-made project visible from the moon.Although it was once thought to have been built entirely during the Qin Dynasty between 221 and 208 BC, it is now believed to have been started earlier.
中国的长城被视为惟一能从月球上看到的人造工程。人们曾认为长城全部修建于公元前22l到208年的秦朝，但现在人们相信长城的修建要开始得更早。
