After more than a decade as a band, Glass Animals are having the biggest moment of their career — with a song that came out two years ago. "Heat Waves," the British indie rock group's infectious, thumping single, hit No. 1 on the Billboard Hot 100 on March 7. Prior to the chart-topping, GRAMMY.com caught up with frontman Dave Bayley about what it means to receive recognition more than a decade in, why the song is so special, and how his band is "still a bunch of 12-year-olds."