At first blush, the midi-skirt might seem like a challenging length. After all, it's the same length as the kind of prom dresses school deans would approve of, graduation gowns, and your babysitter's button-front sundresses — the kind of fusty, adult-approved clothing that is about as cool as Vitamin D milk. But, midis have replaced maxi dresses, micro dresses, and below-the-knee skirts as the hem length du jour because of a very simple reason: they hit your leg at the skinniest part of your ankle, thus, giving you an extra visual boost in height.