When Metallica joined forces with the San Francisco Symphony for 1999’s S&M, there was natural skepticism amongst fans on either side of the genre divide—at a glance, metal and classical music are true opposites, the oddest of couples. But Metallica has long understood the spiritual links between the two. “If there's any sort of dissonance, it's largely optical,” guitarist Kirk Hammett tells Apple Music of the pairing. “There have been musicians in the past who were searching for a sound and a feel like heavy metal, but it just wasn't invented yet. The technology and the sounds weren't there, so they had to settle for what they had at hand, which is string sections and brass. To a certain extent, there was a type of classical music that was the heavy metal of its time.” To celebrate the album’s 20th anniversary, the two outfits reunited to open up San Francisco’s newly completed Chase Center arena with a two-night event in September 2019. Where its predecessor positioned the band in front of the orchestra (at the comparatively modest Berkeley Community Theater), S&M2 finds them fully integrated and playing in the round, thanks in large part to major advances in sound design and cordless mic technology. “This time, it really felt like we were just one big, big, big band,” Hammett says. “For me, it's the ultimate: being able to play a huge, fucking loud power chord, and to hear 70 instruments just fall into place behind it to make it so much bigger.” The set list and string arrangements were subtly updated, to further elevate hits (“One,” “Enter Sandman”) and make way for reimagined highlights from the band’s most recent string of LPs (2003’s St. Anger, 2008’s Death Magnetic, and 2016’s Hardwired…To Self-Destruct). There are moments of both bombast and grace, the most moving a tribute to late Metallica bassist Cliff Burton (a classical music fan who influenced his bandmates’ tastes) and 1983’s “Anesthesia (Pulling Teeth)” by the San Francisco Symphony’s Scott Pingel. And to prove Hammett’s theory, there’s even a role reversal at the show’s halfway point, when the metal pioneers sit in for a segment of Alexander Mosolov’s Iron Foundry, conducted by Michael Tilson Thomas—an example of early-20th-century futurism made even more dizzying here. “I like to think that we're a better band these days,” Hammett says, emphasizing the 2003 arrival of bassist Rob Trujillo. “We're better at tackling obstacles and we're better at writing musical solutions to musical questions. It really, really makes a difference in meeting the quality of musicianship that the orchestra brings.”