Why did Osama bin Laden attack America?

He belived that if he save Muslims from USA he will go to heaven

because USA attack Afghanistan , Palestine "using isreal" , Iraq and Islam in general .

and it is war between each other and at war both side attack each other.

so now after we had killed Osama bin Laden, two of his fellow terrorists avenged Osama, killing 80 inocent civilians. (date unknown)