Your closet is likely full of all kinds of materials — leather, cotton, nylon and polyester, to name a few — that contribute to fashion's sustainability crisis. Biomaterials investigator Dan Widmaier explains how we could look to nature for sustainable replacements for these much-used materials and introduces a leather alternative made from mushrooms that looks great and doesn't harm the environment. "We can make fashion sustainable, and we're going to do it with science," Widmaier says.