Hundreds of shoppers were startled during the daily concert on the world's largest Wanamaker Organ when 688 singers standing incognito in their midst burst into Handel's Hallelujah Chorus. Sponsored by the Opera Company of Philadelphia and Macy's the event featured numerous area musical groups, organists Peter Richard Conte and Fred Haas, and support from the Friends of the Wanamaker Organ. Held at noon in the Grand Court at Macy's palatial Philadelphia department store in the John Wanamaker building on October 30, 2010.