Wherever they may roam these days, Metallica are taking a piece of history with them. In a new documentary short, James Hetfield reveals the origin of his wood-based guitar he's affectionately named "Carl" and how it ties back to a few key moments in their career.

"Carl" was constructed from wood from the band's old garage when they live at 3132 Carlson in the Bay Area. It was one of their first practice spaces and it was the place where the classic albums Ride the Lightning and Master of Puppets were hashed out.

Hetfield states the initial idea for their old garage was much grander, with a plan to move it from its location to their current HQ. "You know what would be cool -- really fucking rock star-like? Let's take the garage from Carlson and put it in this room," said Hetfield. "Let's get the garage and take it apart and put it back together in here." But alas, the plan never came to fruition and the garage was destroyed.

Luckily for the band, some of their old neighbors remembered the significance of the garage and a few years back when Metallica revisited the residence, one of their old friends, Andy Anderson, had kept some of the wood from the destroyed establishment.

Hetfield says he then turned the wood over to Ken Lawrence, who has a history of working with the Metallica musician, and let him craft this special instrument. In the documentary, Hetfield runs down some of the specifics, including the representation of Kirk, Lars, James and Cliff Burton on the fretboard along with the Bay Bridge and the actual garage itself. Those who also like to dig into numerology will also get a kick out of some of the added touches that Lawrence provided on the instrument as well.

Hetfield says he's a fan of the instrument and frequently uses it for "Moth Into Flame" during the band's performances. Learn more about "Carl" in the player above.

10 Unforgettable James Hetfield Moments

Metallica Albums Ranked