http://www.mahoodsculpture.com/bird-in-space-sculpture/
Why is the “bird in space” sculpture so famous?
I was going to say that “if you look at what came before and after it, you will see how remarkable it is” but if you read in this article http://en.wikipedia.org/wiki/Bird_in_Space the section on the lawsuits connected with bringing it into the country including the then legal definition of sculpture and how customs defined it, you will get some idea.
Part of the reason you can ask the question is that you are looking back past all the abstract sculpture that we consider art that was not thought to be so back then
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