The CSO brings the soaring emotional peaks and valleys of Mahler’s Sixth Symphony to Chicago audiences before performing it on Amsterdam’s Concertgebouw stage. The “hammer blows of fate” in the finale seem to foreshadow the tragedies in Mahler’s life, including his own fatal illness. But the symphony brims with life’s pleasures, too, from memories of mountain pastures (listen for the cowbells) to a rapturous portrait of the composer’s wife, Alma.