The 'Humming Chorus' is from the opera Madam Butterfly by Giacomo Puccini. Madam Butterfly was premiered in 1904 and was Puccini's own favourite among his operas. The libretto (text of an opera) was written by Giacosa and Illica and is based on a short story of the same title written by John Luther Long (1898). The opera takes place in a house overlooking Nagasaki, Japan, between 1889 and 1892, just before the outbreak of the Sino-Japanese war. The 'Humming Chorus' is performed in Act Two and is sung by the chorus, off stage, showing the passing of time.