"The piano is kind of the hardware for the software of our programming that goes on year round, " said Zamora, who founded Sing for Hope in 2006 with fellow opera singer Monica Yunus, launching the first piano festival in partnership with British artist Luke Jerram in 2010 when 60 pianos were featured.

WSJ: Summertime outdoor pianos returning to NYC

In the 1930s and '40s, it would have been impossible for an African-American singer, however extraordinary, to sing Wagner's lily-white heroine in an opera production.

NPR: The Sweet Sound of Ruby Elzy

When George Gershwin heard her sing, he cast her in the major role of Serena in his new opera, Porgy and Bess.

NPR: The Sweet Sound of Ruby Elzy