Pianist Mitsuko Uchida joins PT host Fred Child to talk about Mozart's Piano Concerto No. 24. (She says "It is very dark, incredibly tragic," but the lilt in her voice conveys the beauty of that darkness.) And we'll hear her concert performance with the Cleveland Orchestra. Plus two concerts in Vienna: Lang Lang plays Chopin's "Aeolian Harp" Etude in the sumptuous acoustics of the Golden Hall at the Musikverein, and Yefim Bronfman plays the Paganini Etude No. 2 by Franz Liszt, at the outdoor gardens of Schonbrunn Palace.