Hard Rock: when speaking of it, one immediately thinks of Led Zeppelin and Deep Purple (as well as Cream and Free)... I would like to present some examples of lesser-known bands or those not directly associated with the genre.
19 - The Paul Butterfield Blues Band - Everything's Gonna Be Alright - Woodstock - 1969
This track is a blues, but blues is an essential component of Hard Rock, and anyway Buzzy Feiten's solo (at 3:35) is definitely Hard...