Bella Hadid, Lily-Rose Depp, and More Prove Why a Six-Pack is Fashion's Best New Accessory

Aspirational abs aren't just a summer phenomenon anymore. Blame it on the new generation of runway walkers and actresses who, throughout September, have turned the ubiquitous sunny-day crop top into a closet mainstay, incorporating stomach-baring tees, blouses, and even sports bras into street-ready looks--and rendering actual shirts almost obsolete in the process. Bella Hadid is a champion of the cause--the younger of the Hadids has been known to flash her midriff on occasions ranging from airp...