Christa Paffgen is most famous for her stint with the Velvet Underground. Yet as a solo artist, the German chanteuse known as Nico proved to be nearly as influential as Grace Slick and Janis Joplin in terms of challenging notions of how a female pop singer should sound, look and act. Instigated by Andy Warhol's Exploding Plastic Inevitable multimedia event, Nico's relationship with the Velvet Underground lasted only a year, but it yielded underground rock's definitive The Velvet Underground & Nico in 1967. On it she delivered three classics: "Femme Fatale," "All Tomorrow's Parties" and "I'll Be Your Mirror," and established an aesthetic she would continue to explore and manipulate until her death in 1988. You could call Nico a singer-songwriter, but her husky croon owed very little to American folk, rock and soul. She crafted a challenging form of art pop that looked to European modernism for inspiration. The Marble Index, released in 1969, is considered to be her peak as an artist. Critic Lester Bangs once called it "the greatest piece of 'avant-garde classical' 'serious' music of the last half of the 20th century." Not bad for a woman who started as a model for Vogue and Elle.