He took the bandoneon—an instrument invented for German church music—and made it weep tango in ways that scandalized Buenos Aires purists. Astor Piazzolla studied with Nadia Boulanger in Paris, who told him in 1954 to stop writing classical music and embrace the street music of his childhood. He did. Traditionalists booed him off stages, calling his nuevo tango a betrayal. But he kept layering Bach fugues over milonga rhythms, adding jazz dissonance to working-class dance halls. When he died today, Argentina had lost its most controversial musician. The tango he left behind doesn't stay in the past—it breathes.