“Gossip Girl” alum Blake Lively, 37, made an appearance on the red carpet at the annual event in New York City, looking chic ...

Attendees are encouraged to dress according to the theme chosen by the Costume Institute.

These shops might seem homogenous, as if they all carry the exact same coral-colored rompers and flowy maxi dresses. Look a little closer, though, and you might be surprised by what you find.