A Whiter Shade of Pale - Procol Harum (1967)
Progressive Rock, like most things, has two parents: Sgt. Pepper's and Procol Harum. With music lifted from Bach's Air On A G String, this band swept the world off its feet with its melding of rock and classical music. Keith Reid's lyrics don't hurt either, giving us medieval imagery transplanted into the summer of love. It strikes a universal chord. While most people don't know how amazing the rest of the Harum's recorded oeuvre is, they know this song. No wonder it is the most played song ever in British public places!
Covered by countless artists, I have always preferred these two.
And ya gotta love Colosseum's miraculous re-interpretation!