. . .
“Echoes” was where Pink Floyd became Pink Floyd for good.
While there had been prog-leaning experimentation on both 1969’s Ummagumma and 1970’s Atom Heart Mother — and both records have their adherents, even though my favorite part of either record is the recursive Ummagumma album cover — to my ears, “Echoes” was the first time (and only time, if you don’t count “Shine On You Crazy Diamond”) they truly pulled off a side-long song. (Sorry, “Atom Heart Mother.”)