Yoko Ono realizing her Imagine Peace stamp piece: viewers may rubberstamp those very words onto maps pinned to the walls.

The entrance to Utopia Station where Yoko Ono's pieces are on view.

The Imagine Piece rubberstamp.

Imagining peace all over the world.

Yoko Ono to Libération in August 2003: "I noticed that the visitors rubber-stamp mostly their own country on the maps. It is beautiful, I think."