Cloud Gate - Higher resolution
It's a magnificient piece of sculpture (weights approx 110 ton). You should definitely check it out (Millennium Park) when in Chicago. It magically blends the surroundings into the displaying piece itself. It "changes" with the sky.
It is nick named "The Bean" by the locals.
It's also British artist Anish Kapoor's first public outdoor work installed in the United States. Here is an URL to some more info on her: