Me atop of the world.
It was the tallest building in the world from 1973 – 1998, until it was surpassed by Petronas Twin Towers in Malaysia. (The reigning tallest building in the world since 2008 is the Burj Khalifa in Dubai.)
The view from Willis Tower Skydeck is breathtaking. Though it is an expensive elevator ride ($23) to get to the viewing area. I wonder if you get a bargain price if you climb the stairs to the Skydeck, which is a mere 103 floors.