Few bands have so fundamentally affected the American music scene—with a single song, no less—as Nirvana did in 1991 with the debut of Smells Like Teen Spirit. The Beatles did it in 1964 with "Please Please Me" and set off the British Invasion, Grandmaster Flash did it in 1981 with "The Message" and brought Hip-Hop to the masses.

But when Nirvana's single hit MTV, it not only ushered in the Grunge era, it single-handedly killed off hair metal and forced the music industry in an entirely new direction—MTV exploded with angst-filled tunes practically overnight and the dance hall garbage that had permeated hit charts through the late 1980s fell off faster than their disco predecessors.

For those of you not around to witness this seminal moment 20 years ago, it would be like a new YouTube star ending Justin Bieber's career with a single song (*fingers crossed*) while simultaneously inventing a new musical genre and telling the RIAA to blow. [Open Culture]