was being shot for an eight-part hbo documentary about the history of modern american music that dave grohlde focuses on the unique musical heritage of one city. to help him learn that histor, grohl interviewed local musicians everywhere the band went, among them troy andrews, better known as "trombone shorty." >> grohl: where you from? >> trombone shorty: from new orleans, from here, treme neighborhood. >> grohl: when i interview these people, i get them to explain not only the history of the city, but the influence that that has on the music that comes from here. there's a reason why chicago blues sounds like chicago blues. and there's a reason why jazz music is here, in new orleans. >> cooper: and the reason is... is the history of how that music was formed. >> grohl: it could be anything. in seattle, it rains all the time, so people stay in their basements and write songs. >> cooper: grohl approached the project as a both a musician and a historian, and says he was often surprised about what he learned. >> grohl: well, everybody knows nashville as the country music capital of the world.

. ♪ you know i'm not in the clear ♪ >> cooper: dave grohl, the band's leader, invited us to watch astraveled to eight american cities, interviewed some of the most influential musicians to record all that's great about american music. >> i'm steve kroft. >> i'm lesley stahl. >> i'm bob simon. >> i'm anderson cooper. >> i'm bill whittaker. >> i'm norah o'donnell. >> i'm scott pelley. those stories tonight on "60 minutes." bipolar depression, ling with there are treatment options. ask your doctor if once-a-day latuda, lurasidone hcl, may help you. in clinical studies, latuda has been shown to be effective for many people struggling with bipolar depression. latuda is not for everyone. call your doctor about unusual mood changes, behaviors, or suicidal thoughts. antidepressants can increase these in children, teens, and young adults. elderly dementia patients on latuda have an increased risk of death or stroke. call your doctor about fever, stiff muscles and confusion, as these may be signs of a life-threatening reaction or if you have uncontrollable muscle movements, as these may be per