In commemoration of Billboard's 60th anniversary, the editors of the magazine have listed the 100 "most massive artists" to hit the charts over the past six decades. Predictably the Beatles topped the list, followed by Madonna, with Elton John coming in at three. Elvis Presley followed at Number Four, and Mariah Carey at five. Honorable mention goes to Stevie Wonder who just missed the Top Five, coming in at number six.

The Top 25 'Most Massive Artists' according to Billboard's chart calculations:

1. The Beatles

2. Madonna

3. Elton John

4. Elvis Presley

5. Mariah Carey

6. Stevie Wonder

7. Janet Jackson

8. Michael Jackson

9. Whitney Houston

10. Rihanna

11. The Rolling Stones

12. Paul McCartney

13. The Bee Gees

14. Usher

15. Chicago

16. The Supremes

17. Prince

18. Daryl Hall & John Oates

19. Rod Stewart

20. Olivia Newton-John

21. Drake

22. Aretha Franklin

23. Marvin Gaye

24. Taylor Swift

25. Katy Perry

George Harrison explained that creating a new musical and aural template was the reason for the Beatles' long hours in the studio: "A lot of the time was spent, actually, just trying to get sounds and trying to find sounds -- invent them. Nowadays it's pretty easy; in fact it's too easy. There's so many sounds available just by hittin' a button. And all of these machines -- because of some of those records in the '60s -- they invented machinery where you just switch it on and you instantly get an effect."

AUDIO: STEVIE WONDER ON WRITING 'SONGS IN THE KEY OF LIFE'
AUDIO: JOHN MELLENCAMP ON ELVIS PRESLEY
AUDIO: MICHAEL JACKSON ON GOING PLATINUM
AUDIO: ELTON JOHN ON TREMENDOUS OUTPUT DURING THE '70S
AUDIO: RRHOF MADONNA TALKS ABOUT ROLLING AROUND AT THE MTV AWARDS
AUDIO: GEORGE HARRISON ON THE BEATLES INVENTING SOUNDS