Blues rock is a fusion genre combining elements of blues and rock. It is mostly an electric ensemble-style music with instrumentation similar to electric blues and rock: electric guitar, electric bass guitar, and drums, sometimes with keyboards and harmonica. From its beginnings in the early- to mid-1960s, blues rock has gone through several stylistic shifts and along the way it inspired and influenced hard rock, Southern rock, and early heavy metal. Blues rock continues to be an influence in the 2010s, with performances and recordings by popular artists. Blues rock started with rock musicians in the UK and the US performing American blues songs. They typically recreated electric Chicago-style blues songs, such as those by Muddy Waters, Jimmy Reed, Howlin' Wolf, and Albert King, at faster tempos and with a more aggressive sound common to rock. In the UK, the style was popularized by groups such as the Rolling Stones, the Yardbirds, and the Animals, who placed several blues songs into the pop charts. In the US, Lonnie Mack, the Paul Butterfield Blues Band, and Canned Heat were among the earliest exponents and later "attempted to play long, involved improvisations which were commonplace on jazz records". John Mayall & the Bluesbreakers and Peter Green's Fleetwood Mac also developed this more instrumental, but traditional-based style in the UK, while late 1960s and early 1970s groups, including Ten Years After, Savoy Brown, the Climax Blues Band and Foghat became more hard rock oriented. In the US, Johnny Winter, the Allman Brothers Band, and ZZ Top represented a hard rock trend. Along with hard rock, blues rock songs became the core of the music played on album-oriented rock radio, and later the classic rock format birthed in the 1980s. Although around this time, the differences between blues rock and hard rock lessened, there was also a return to more blues-influenced styles. In the 1980s, the Fabulous Thunderbirds and Stevie Ray Vaughan, recorded their best-known works and the 1990s saw guitarists Gary Moore, Jeff Healey, and Kenny Wayne Shepherd become popular concert attractions. Groups such as the Jon Spencer Blues Explosion and the White Stripes, brought an edgier, more diverse style into the 2000s, as do contemporary artists such as the Black Keys.