A new museum wing ... in a giant bubble

How do you make a great public space inside a not-so-great building? Liz Diller shares the story of imagining a welcoming, lighthearted -- even, dare we say it, sexy -- addition to the Hirshhorn Museum in Washington, DC. (From The Design Studio session at TED2012, guest-curated by Chee Pearlman and David Rockwell.)