Pull the tab, and it actually moves. Andy Warhol built a real, working brass zipper into the front of Sticky Fingers, embedding it in a close-up photograph of a man's crotch packed into tight jeans. In 1971, putting a male groin at full-frame scale on a major-label album was genuinely transgressive, and the metal teeth turned an act of looking into an act of touching.

The image is a provocation and a dare rolled into one, at once a joke, a come-on, and a comment on rock-and-roll sexuality. Where most sleeves asked only to be seen, this one asked to be handled, making the buyer a participant before the needle ever reached the groove. Warhol's premise was simple and outrageous, and it dared you to complete it yourself.

Who wore the jeans has been argued over for half a century. And the zipper that made the cover so hard to ignore would prove just as hard to ship.