Initially forming in the late ‘80s, Chris Thile and siblings Sean and Sarah Watkins blasted the boundaries of bluegrass wide open when they broke through in the early ‘00s, bringing a sound that took the trio's down-home roots and expanded them in several directions at once. Nickel Creek took the basic building blocks of bluegrass like mandolin, fiddle, acoustic guitar, and super-tight vocal harmonies, and used them to move whichever way they wanted, be it in jazz-fusion-inflected instrumentals like "Smoothie Song," folk-flavored ballads like "When You Come Back Down," or explosions of pure pop like "Destination."