According to the NASA website, the definition of where �space' begins is (quote)...
"the lowest altitude that permits a vehicle to orbit the earth without entering the earth's atmosphere. That altitude is approximately 100 km (62 miles)."
Outer space begins where the laws of aerodynamics no longer apply, which is at around 90 miles up.
So, space begins around 60 miles above the earth's surface. Thus, asking what man-made things are visible from �space' gets the answer: "From that height, there are lots of visible man-made things." These are things such as cities, roads, airports, harbours, bridges, tankers at sea and so on.
If you meant to say 'From the moon's surface...' - which is the usual form of this question - the answer is "Nothing." (Apart, that is, from the module the guys there landed in, which is on the moon with them!)
Seeing the Great Wall of China from space has been confirmed by astronauts, but seeing it from the moon - which is about a quarter of a million miles away, not just 60! - is exactly as likely as seeing a schoolboy's 12-inch ruler from 400 miles away right here on earth!