Michael Tilson Thomas conducts the San Francisco Symphony. Bill Swerbenski/San Francisco Symphony hide caption

itoggle caption Bill Swerbenski/San Francisco Symphony

Composer Meredith Monk being interviewed during the 'American Mavericks' event at The Greene Space, New York City, on March 26, 2012. Matthew Septimus/courtesy of New York Public Radio hide caption

itoggle caption Matthew Septimus/courtesy of New York Public Radio

Composer Henry Brant took 36 years to transform the "Concord" sonata by Charles Ives into a full-fledged symphony. SFS Media hide caption

itoggle caption SFS Media

Projections on the giant sails of the Sydney Opera House, which served as the venue for the YouTube Symphony Orchestra concert. Chris Phillips/YouTube hide caption

itoggle caption Chris Phillips/YouTube