This is not to be confused with the former. There were low-slung pants, paired with regular length tops that exposed just a strip of skin and then there were full-on, basically-a-bra crop tops. These, as it turns out, went excellently with low slung jeans and another important aughties staple: the belly button ring. As you can see, Keira Knightley is hitting all the right notes here in 2003. The thing is: The crop top hasn’t really gone out of style yet. But if it starts showing up with low-waisted denim, and some navel jewelry then yep, it’s an aughts reference.