The first time I heard Little Big Town, I knew they needed to play the Tiny Desk. This was eight years ago, when the country foursome made a splash with the playful hit "Pontoon." The easy fun these friends projected won me over, but I stayed for the crazy powerful harmonies. I soon discovered that Little Big Town had been perfecting its vocal blend for more than a decade – and the group just got better, and more adventurous, as its star rose. In 2014 came the spine-tingling ballad "Girl Crush," in 2017 the Taylor Swift collaboration "Better Man." Both songs won Grammys. This year Little Big Town topped itself with its ninth album, Nightfall, a perfect balance of meditative moments and bangers that extends its reign as country's greatest contemporary quartet.