R.E.M. marked the point when post-punk turned into alternative rock. When their first single, "Radio Free Europe," was released in 1981, it sparked a back-to-the-garage movement in the American underground. While there were a number of hardcore and punk bands in the U.S. during the early '80s, R.E.M. brought guitar pop back into the underground lexicon. Combining ringing guitar hooks with mumbled, cryptic lyrics and a D.I.Y. aesthetic borrowed from post-punk, the band simultaneously sounded traditional and modern. Though there were no overt innovations in their music, R.E.M. had an identity and sense of purpose that transformed the American underground. Throughout the '80s, they worked relentlessly, releasing records every year and touring constantly, playing both theaters and backwoods dives. Along the way, they inspired countless bands, from the legions of jangle pop groups in the mid-'80s to scores of alternative pop groups in the '90s, who admired their slow climb to stardom.