If it wasn’t for the wooden wall separating Kirk Hammett and the crowd before Metallica’s October 12th, 1991, Day On The Green performance at the Oakland Coliseum, it would be impossible to tell who was the rock star and who were the fans, reports San Francisco Chronicle's Peter Hartlaub.

Metallica was arguably the biggest rock band in the world, just two months after the debut of Metallica - the so-called Black Album that would go 16x platinum. But Hammett ran below the stage bumping fists with the crowd, in his “Horror-Thon” T-shirt with classic movie monsters on the front, and a smile on his face like he was playing in a garage again.

The Chronicle story that followed focused on the violence in the mosh pits, and the damage to the Coliseum baseball field that included large chunks of grass pulled out by rowdy heavy metal fans. But time and perspective prove that the big show was a breakthrough moment for Metallica - which continues to headline local arenas, and continues to call the Bay Area home.

The colour images were discovered during a search for photos, to accompany an episode of the “The Big Event” podcast that pays tribute to the 1988 … And Justice For All album. Instead, more than three dozen 1991 Day On The Green photos were found, with about half featuring the crowd and half featuring the band.

Read more and check out a photo gallery at sfchronicle.com.

(Photo - Ron Riesterer, The Chronicle)