A: The Great Wall is not visible to the naked eye from space. On the evening of October 16, 2003, Bai Yansong, the host of China Central Television, asked Yang Liwei, China's first astronaut, "Did you see the Great Wall that everyone is talking about when you were in space?" Yang Liwei replied, "The Earth looked very beautiful from space, but I did not see our Great Wall.”
It shows that the Great Wall of China cannot be seen by astronauts without an optical aid, so that the statement that "the Great Wall of China is the only manmade structure visible from space" is not tenable.
In fact, even in the best conditions of atmospheric visibility, human vision can only reach tens of kilometers without the aid of any external equipment. It is also difficult to see the Great Wall from the Central Radio & Television Tower located in central Beijing in the best weather conditions.