Tod Machover: Composer's social media symphony for Toronto
12 March 2013 Last updated at 00:20 GMT
Imagine collaborating with a classical composer to create a symphony about your hometown. The people of Toronto, Canada, have done exactly that.
On Saturday 9 March, residents were treated to a ground-breaking concert that was the result of an almost year-long project.
Sounds recorded by volunteers across the city - everything from noisy traffic to children's voices - were woven together with the strings and horns of a traditional orchestra. Contributions were invited via the internet and the audience were even able to manipulate the ending of the music via an app.
Composer Tod Machover, who is also a technologist at the Massachusetts Institute of Technology, and Peter Oundjian, the music director at the Toronto Symphony Orchestra, explain how the innovative idea worked.
Produced for the BBC by Anna Bressanin; camera by Ilya Shnitser