Master of Puppets is Metallica's third studio album, released in March 1986. It was recorded at Sweet Silence Studios in Copenhagen under producer Flemming Rasmussen and is the last album to feature bassist Cliff Burton, who died in a bus accident in September 1986. The title track deals with addiction, while the instrumental Orion gives a central role to Burton's bass playing. Other tracks include Battery, Welcome Home (Sanitarium) and Disposable Heroes. In 2016 Master of Puppets became the first metal album added to the National Recording Registry.