What's Really Visible from Space: space.com

[Ivan Seeking]

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.

http://space.com/scienceastronomy/visible_from_space_031006.html

[Zantra]

this is cool. About 5 years back microsoft created the terradata.com database with arial views of the entire US and most of the world that you could pull up and view. not sure if it still exists, but it was pretty cool- I was able to pull up my city and basically see my house-from a few years back.

[Guybrush Threepwood]

what I've heard is that the Great Wall was visible from the moon.
(although never found a picture to confirm this...)

Evidently there are a lot of things visible from space. Depends how high you are...[:)]