Grunge operated underground in 1980s Seattle, staying there until the end of 1991 when MTV put Nirvana's "Smells Like Teen Spirit" video into constant rotation -- at which point Grunge unwittingly went global. Pacific Northwest proto-grungers -- Tad, the Melvins, and Green River, to name a few -- took the sludgiest elements of early '70s metal and updated it with Punk fervor in the mid/late'80s. Mudhoney, Soundgarden and Nirvana began adding more melodies to the Grunge template by the end of the decade, by which point Seattle's Sub Pop Records (home to all three bands) had become the world's de facto Grunge production line. Nirvana chose a pop-influenced route ("Sliver"), Soundgarden assumed the role of metal masters ("Outshined"), Mudhoney raised garage rock to a new level ("Touch Me, I'm Sick"), and newcomers Pearl Jam updated '70s and '80s Hard Rock ("Even Flow"). Later in the '90s, streamlined Post- Grunge and Grunge-Pop acts such as Stone Temple Pilots, Everclear, Matchbox 20 and Bush musically acknowledged many late '80s/early '90s Grunge bands as primary influences.