Which flag inspired the coiled snake on the cover of Metallica's 1991 self-titled album?

The coiled snake on the cover of Metallica's 1991 self-titled album was derived from the Gadsden flag. The cover places the snake in the lower-right corner beneath the band's angled logo.

The Gadsden flag is an American historical flag featuring a rattlesnake and the motto “Don't Tread on Me.” That motto also appears as the title of one of the album's songs, creating a direct connection between the artwork and the track list.

The original packaging made the design extremely subtle. The Metallica logo and snake were embossed so they were difficult to see against the black background. Later releases used dark gray elements that stand out more clearly, but the basic imagery remained the same.

The album's official title is simply Metallica. Listeners began calling it The Black Album because of the nearly black cover, not because the record was formally titled that way. The artwork's understated appearance became one of its most recognizable features.