The most abrasive and aggressive fusion of rock and electronic music, industrial was initially a blend of avant-garde electronics experiments (tape music, musique concrète, white noise, synthesizers, sequencers, etc.) and punk provocation. As industrial evolved, its avant-garde influences became far less important than its pounding, relentless, jackhammer beats, which helped transform it into a darker alternative to the hedonism of mainstream dance music. Industrial's trademark sound was harsh and menacing, but its rage was subordinate to the intentionally mechanical, numbingly repetitive qualities of the music, which fit the lyrics' themes of alienation and dehumanization quite well. In the early '90s, Ministry and Nine Inch Nails took their variations on industrial to wider alt-rock and metal audiences, but a substantial number of industrial artists chose to remain underground. The first group of industrial bands -- England's Throbbing Gristle and Cabaret Voltaire, and Germany's Einsturzende Neubauten -- were initially as much about beyond-edgy performance art as they were music. The second generation of industrial artists -- including Skinny Puppy, Front 242, and Nitzer Ebb -- added pummeling dance beats to their predecessors' confrontational sounds, for a substyle often referred to as electronic body music (centered around labels like Wax Trax). Meanwhile, bands like Ministry and KMFDM added metal-guitar riffs, which helped Ministry break through to a wider audience in the late '80s and early '90s; similarly, Nine Inch Nails' Trent Reznor added more traditional song structures, and made his own persona the focal point, giving the music a rare human presence and becoming a star in the process. This more widely appealing strain of industrial continued to influence alternative metal throughout the '90s. Still, after industrial metal began to fade, a near-exclusively electronic form of industrial dance continued to thrive as an uncompromisingly underground style, with many artists coming from the U.S. and Germany.