Which flag inspired the snake depicted on the cover of Metallica's 1991 album?

The snake on the cover of Metallica's 1991 album was derived from the Gadsden flag.

The cover places Metallica's logo in the upper-left corner and a coiled snake in the lower-right. On the initial release, both elements were embossed against a black background, making them difficult to see and inspiring the album's common nickname, The Black Album.

The Gadsden flag is historically associated with a coiled rattlesnake and the motto “Don't Tread on Me.” That motto also became the title of one of the album's songs, creating a direct visual and thematic link between the packaging and the track list.

Later editions made the logo and snake dark gray so they stood out more clearly. The cover's minimalist design was deliberate, contrasting with the elaborate artwork of several earlier Metallica albums.