>>> heartburn. we sing it every new year's eve. " auld lang syne." it's a catchy tune but what does it mean and what are the words? one poll found that 75% of people will be making up the lyrics later tonight. a museum in new york city has a whole exhibit dedicated to that one famous song.

>> reporter:  millions of us sing it every new year's eve. well, fake it, anyway. it's been called the most famous song that we don't note lyrics to.

>> " auld lang syne."

>> be forgot keep your eye on --

>> reporter:  billy crystal even ranted about it in "when harry met sally."

>> what does this song mean? my whole life i don't know what this song means. should old acquaintance be forgotten? does that mean we should forget old acquaintance? if we don't remember them we should remember them because we already forgot them.

>> reporter:  within the stacks of this museum a new exhibit has the answers starting with the origins of the song.

>> the tune has been knock about for the best part of the 18th century in various incarnations.

>> reporter:  back in the late 1700s, the celebrated scottish poet robert burns penned the words claiming he heard it from an old man singing.

>> shoulder old acquaintance be forgot and never brought to mind? should old acquaintance be forgot and days " auld lang syne."

>> it literally means "old long since." this of it as "for old time's sake". it was written during a time people were pining for the old days.

>> that was very much the way scottish people were feeling at end of the 18th century. they were going to be annexed to great britain. there's a tone of something lost there.

>> reporter:  after burns died the lyrics were set to a wedding song and combined into its final form in 1799. but it wasn't until big band leader guy lombardo played " auld lang syne" at a new york city new year's eve party that it was born. that first line is rhetorical. "no, we shouldn't forget our old friend" just like george bailey learned in "it's a wonderful life." it's nostalgic. emotional, even.

>> you kind of tear up when you sing it. because it makes you think about people you miss.

>> we'll take a cup of kindness yet for old time's