Sonic Highways is an album accompanying the Dave Grohl–directed documentary of the same name, which follows the Foos as they explore American music's roots in cities like Chicago, Austin, and Los Angeles. While Grohl's lyrics are lifted from interviews with greats like Buddy Guy and Dr. John, the band keep their driving alt-rock sound intact. "Outside" rides a gnarled punk bassline to a cathartic chorus and includes a guitar solo from Joe Walsh, while "Congregation," tracked in Nashville, boasts a Southern rock crunch. With its epic, string-section grandeur, the standout "I Am a River" captures the resiliency of New York, the city where it was recorded.