I've been to Niagara Falls more times than I can count, and it is ALWAYS simply incredible. I've stood by the falls for hours, until soaked by the spray. I've also been there when the smaller section (The American falls) was frozen.
An American castle.The Biltmore Estate, Asheville, NC. When I was a child I said I was going to grow up and buy this place. It's an amazing house. I was fascinated by the kitchen and the views! Not to mention the gardens.