Ground Zero

Do you know 'Ground Zero'?
It's a place where the World Trade center(WTC) was.
But you know, now there is a memorial park for the casualties after a terrible accident. I don't know who was right. Because. If the USA didn't attack the Iraq,
Osama would be quite in their nation.
Imperialism of the USA make many countries fall off..
So they made their casualties by their hands.