query: When did construction on the Great Wall of China begin?
passage: History of the Great Wall of China
The history of the Great Wall of China began when fortifications built by various states during the Spring and Autumn (771–476BC)[1] and Warring States periods (475–221BC) were connected by the first emperor of China, Qin Shi Huang, to protect his newly founded Qin dynasty (221–206BC) against incursions by nomads from Inner Asia. The walls were built of rammed earth, constructed using forced labour, and by 212 BC ran from Gansu to the coast of southern Manchuria.
passage: Great Wall of China
In 2001, Neil Armstrong stated about the view from Apollo 11: "I do not believe that, at least with my eyes, there would be any man-made object that I could see. I have not yet found somebody who has told me they've seen the Wall of China from Earth orbit.... I've asked various people, particularly Shuttle guys, that have been many orbits around China in the daytime, and the ones I've talked to didn't see it."[71]