Cloud Gate.

"What I wanted to do in Millennium Park is make something that would engage the Chicago skyline ... so that one will see the clouds kind of floating in, with those very tall buildings reflected in the work. And then, since it is in the form of a gate, the participant, the viewer, will be able to enter into this very deep chamber that does, in a way, the same thing to one's reflection as the exterior of the piece is doing to the reflection of the city around."

- Anish Kapoor, Sculptor