On Monday, Sia dropped a new song called "The Greatest." The accompanying video, which stars often-favoured Sia dancer Maddie Ziegler, serves as a haunting tribute to June's Pulse nightclub shooting in Orlando. With 49 dancers representing the 49 lives claimed, the video transcends its medium to emphasise the great loss endured by the attack. We've seen moving performances from Ziegler's work before; the music video for "Big Girls Cry" and "Elastic Heart" with Shia LaBeouf are each beautiful in their own right. That said, this is arguably Sia's (and Ziegler's) most emotional work yet.