critics were complimentary. At an all-Ravel programme conducted by Serge Koussevitzky in New York, the entire audience stood up and applauded as the composer took his seat. Ravel was touched by this spontaneous gesture and observed, "You know, this doesn't happen to me in Paris." Orenstein, commenting that this tour marked the zenith of Ravel's international reputation, lists its non-musical highlights as a visit to Poe's house in New York, and excursions to Niagara Falls and the Grand Canyon. Ravel was unmoved by his new international celebrity. He commented that the critics' recent enthusiasm was of no more importance than their earlier judgment, when they called him "the most perfect example of insensitivity and lack of emotion". The last composition Ravel completed in the 1920s, Boléro, became his most famous. He was commissioned to provide a score for Ida Rubinstein's ballet company, and having been unable to secure the rights to orchestrate Albéniz's Iberia, he decided on "an experiment in a very special and limited direction... a piece lasting seventeen minutes and consisting wholly of orchestral tissue without music". Ravel continued that the work was "one long, very gradual crescendo. There are no contrasts, and there is practically no invention except the plan and the manner of the execution. The themes are altogether impersonal." He was astonished, and not wholly pleased, that it became a mass success. When one elderly member of the audience at the Opéra shouted "Rubbish!" at the premiere, he remarked, "That old lady got the message!" The work was popularised by the conductor Arturo Toscanini, and has been recorded several hundred times. Ravel commented to Arthur Honegger, one of Les Six, "I've written only one masterpiece – Boléro. Unfortunately there's no music in it." Last years At the beginning of the 1930s Ravel was working on two piano concertos. He completed the Piano Concerto in D major for the Left Hand first. It was commissioned by the Austrian pianist Paul Wittgenstein, who had lost his right arm during the war. Ravel was stimulated by the technical challenges of the project: "In a work of this kind, it is essential to give the impression of a texture no thinner than that of a part written for both hands." Ravel, not proficient enough to perform the work with only his left hand, demonstrated it with both hands. Wittgenstein was initially disappointed by the piece, but after long study