Mahler composed his First Symphony when he was only 28, yet it has many of the features that characterize his later work--a huge orchestra, vastness, an inseparable relationship with song. The second lied from his Songs of a Wayfarer forms the primary, joyful theme of the first movement, which emerges out of an amorphous haze of nearly inaudible sound and an otherworldly stillness. The second movement is all earth--robust, exuberant, full of folk-dance rhythms. The third, with its languorously slow canon based on "Frere Jacques," can be hypnotic: the rocking motion of the muted double basses playing the canon's repetitive theme up and down draws us into this monumental movement as it adds layer upon layer of instruments to create an enveloping warmth. It's also full of surprises--a somber funeral march that's continually interrupted by a swinging clarinet descant, followed by eastern European street music that spins out of control, then evolves into richly orchestrated schmaltz. Mahler's remarkable ability to keep reinventing thematic material in an organic, seemingly spontaneous way is also heard throughout the stormy and lush fourth movement and its calm, poetic ending. James Conlon, who's conducted nearly every major American and European orchestra since his 1974 New York Philharmonic debut, will kick off his tenure as music director at Ravinia with this program, which also includes a performance of the Second Symphony of Viktor Ullmann, a Jewish composer who wrote much of his music in Terezin and died in Auschwitz. It's the first work in Conlon's multiyear project showcasing the music of composers affected by the Holocaust, "Breaking the Silence." Fri 6/24, 8 PM, Pavilion, Ravinia Festival, Green Bay and Lake Cook Rds., Highland Park, 847-266-5100, $10-$40.