The Great Wall of China - "a dragon winding over the mountains"
So... can the Great Wall of China really be seen from space? This statement from NASA answers the question: "The Great Wall of China, frequently billed as the only man-made object visible from space, generally isn't, at least to the unaided eye in low Earth orbit. It certainly isn't visible from the Moon." This website explains further and has pictures of the Great Wall as "seen" from space: http://www.nasa.gov/vision/space/workinginspace/great_wall.html