Lollapalooza Festival.Chicago’s very own music extravaganza welcomed the heavy metal icons for an unforgettable performance of their greatest hits for the first time since their last appearance at the festival in 2015.The band even gave a special shoutout to Netflix’s hit show “Stranger Things” which helped introduce an entirely new generation to Metallica’s music.The show famously featured the band’s hit track “Master of Puppets” in season 4, which instantly went viral and racked up millions of listens on streaming platforms.And none other than frontman James Hetfield expressed gratitude to the show’s producers for feating the track.“Forty-one years to still be up here kicking your asses and you still kicking ours … we were born to do this and we’re glad we’re still doing it,” Hetfield told the crowd before asking how many first-timers were in the audience.