Backstreet Boys, Millennium: 1,134,000
Release Date: 5/18/1999
Backstreet Boys prepped for Y2K with one of the best selling records of all time. The album stayed at No. 1 on the Billboard 200 for 10 non-consecutive weeks and broke records by selling 500,000 copies on its first day. It was the best selling album of 1999 and has sold 28 million copies worldwide.