The Metallica-curated Orion Fest announced that it will return for a second year on June 8 + 9, transplanting itself from Atlantic City, New Jersey to Detroit, Michigan. Last year's lineup featured everyone from Baroness and Suicidal Tendencies to Modest Mouse and Gary Clark Jr. and while the lineup for the 2013 edition hasn't been announced yet, expect similar heavyweights next year. We all love Metallica, but to amp you up, we've compiled this Roots of Metallica playlist, featuring an hour's worth of the band's influences. It ranges from the legendary (Iron Maiden) to the obscure (Tygers of Pan Tang!) but it all rocks.