The natural descendant of the 8-track—which used similar magnetic tape but housed it in a much bigger, bulkier frame—the audio cassette was the brainchild of engineers at Philips. It's precise birthday is open to some debate, but Philips is insistent that the format was officially launched at its Amsterdam HQ on September 13th, 1963. Containing a length of audio tape 3.15 millimeters wide that ran at 1-7/8 inches per second, it was originally designed to replace reel-to-reel tape for dictation—but became far more popular than that.
While the tape is now an object that would confuse teenagers worldwide—superseded initially by CDs and all manner of new technologies since—for many of us it's both an iconic object and a source of misty-eyed nostalgia. Whether it be compiling a mix tape with expert precision, queueing at the music store to pick up that copy of Nevermind, or cruising a highway while popping one into your car's dash, there's surely no shortage of fond memories to recall.
Remember how your cassette player used to chew tapes up with seemingly now warning? How they slowly deteriorated in quality when you listened to them over and over? The way you had to time songs in order to make them fit on your mix tape? Or that horrible noise they used to make on rewinding? Ah, those were the days. Long live the cassette tape. More here.