Chris Thile is at a crossroads. His marriage has ended and his platinum-selling band, Nickel Creek, has gone on hiatus. But Thile, a prodigy who has defied expectations since he picked up the mandolin at age five, has a plan.

Punch Brothers, performing live at the legendary Blackbird Studio in Nashville, Tennessee.

Examine the history of bluegrass music, from its origins to its eventual worldwide popularity, and hear from dozens of musicians who explain the ways bluegrass music transcends generational, cultural and geographic boundaries.