Nessun dorma is an aria from the final act of Giacomo Puccini's opera Turandot, one of the best-known tenor arias in all of opera. The piece is known for its demanding vocal requirements and its powerful, emotional climax. The title translates to "None shall sleep" from Italian, referring to Princess Turandot's decree that no one in Peking may sleep until Calaf's name is discovered.