What Does It Mean To Be 'Cool'? The Smithsonian Is Here To Explain

WASHINGTON (AP) — Curators at the National Portrait Gallery want to know what it means to be cool.

It's a uniquely American concept with roots in jazz slang that's become a global obsession. Over the past five years, curators have chosen 100 photographs of people who helped define cool as a word for rebellion, self-expression, charisma, edge and mystery.

In a new exhibition opening Friday, that hard-to-define concept gets a scholarly treatment. "American Cool" traces the idea back to the "granddaddies of cool," Walt Whitman and Frederick Douglass, and unfolds through the generations, leading to Jay-Z, Johnny Depp and Madonna....