Hard rock:

Groups that emerged from the American psychedelic scene about the same time included Iron Butterfly, MC5, Blue Cheer and Vanilla Fudge. San Francisco band Blue Cheer released a crude and distorted cover of Eddie Cochran's classic "Summertime Blues", from their 1968 debut album Vincebus Eruptum, that outlined much of the later hard rock and heavy metal sound. The same month, Steppenwolf released its self-titled debut album, including "Born to Be Wild", which contained the first lyrical reference to heavy metal and helped popularise the style when it was used in the film Easy Rider (1969). Iron Butterfly's In-A-Gadda-Da-Vida (1968), with its 17-minute-long title track, using organs and with a lengthy drum solo, also prefigured later elements of the sound.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What song was used in the film Easy Rider in 1965?
unanswerable