The year 1975 was a very good one for Elton John and Chicago. It was pretty good as well for artists from Olivia Newton-John to Led Zeppelin, too.

Billboard is ranking the Top 200 Albums of the 21st Century, and we're sharing our some albums in the top five and how they broke records on the Billboard 200. What's your favorite album of all time?

In the 21st century, music became more universal, immediate, and accessible than ever before. On Jan. 1, 2000, the average cost of a CD was about $18, which meant if you wanted to legally own 250 albums,