Some Riffs and a Trip!!!

Wikypedia.com define riffs así:
"In music, a riff is an ostinato figure: a repeated chord progression, pattern, refrain or melodic figure, often played by the rhythm section instruments, that forms the basis or accompaniment of a musical composition (though they are most often found in rock music, Latin, funk and jazz)."

Uno de los riff más famosos del rock!
Iron Man - Black Sabbath


Black Dog - Led Zeppelin


Smoke on the Water - Deep Purple


Aqualung - Jethro Tull


Kashmir - Led Zeppelin


Esto no es un riff, es un viaje!
Eruption!