text: what man-made feature can be seen from space today?   there is a longstanding myth that the great wall of china is the only manmade object visible from space. it and several variations on the theme are great fodder for water cooler arguments. in reality, many human constructs can be seen from earth orbit.  shuttle astronauts can see highways, airports, dams and even large vehicles from an earth orbit that is about 135 miles (217 kilometers) high. cities are clearly distinct from surrounding countryside, and that's true even from the higher perch of the international space station, which circles the planet at about 250 miles (400 kilometers) up.   full story at: http://www.space.com/scienceastronomy/visible_from_space_031006.html