The Eagles Greatest Hits 1971-1975 came out today back in 1976, and since then it has become the #1 selling album of all time in the United States.  OK, to be fair, I'm not acknowledging Michael Jackson, who actually shares the title with them.

Maybe you think a "compilation" album should be in a separate category, maybe you don't,  but what I find most surprising is that it beat Dark Side of The Moon.  Pink Floyd's masterpiece is the second best selling album of all time around the whole globe, but here in the U.S. it's surprisingly 5th.  Our RIAA top 3 in the U.S. are:

1.   Eagles Greatest Hits 71-75    2.  Led Zeppelin IV     3.  AC/DC Back in Black.