The Mariinsky Theatre Second Stage hosted which Russo-Austrian soprano on May 2, 2013?
Mariinsky Theatre Second Stage:  The Second Stage has been completed and a gala concert celebrating the opening, and featuring such luminaries as Plácido Domingo, Rene Pape, Anna Netrebko, and many others, was presented on 2 May 2013. Anna Netrebko: Anna Yuryevna Netrebko (Russian: Анна Юрьевна Нетребко , born 18 September 1971) is a Russian operatic soprano. Anna Netrebko:  She now holds dual Russian and Austrian citizenship and currently resides in Vienna, Austria, and in New York City.
Anna Netrebko