Master of Puppets was originally released in 1986 and went on to become the first Metallica album to be certified Platinum by the RIAA. The album has been certified six-times Platinum in the United States and has sold over 10 million copies worldwide. In 2016, the album became the first metal album to be added to the National Recording Registry of the Library of Congress, an honor granted to works deemed "culturally, historically, or aesthetically significant." Master of Puppets was the band's last album to feature bassist Cliff Burton, who died in a bus accident in Sweden during the album's promotional tour.