Athletic-wear giant Adidas has been making strides in the effort to produce sneakers with sustainable materials. In recent years, it has incorporated materials made from recycled plastic, which has been reclaimed from beaches and coastal regions, into the manufacture of its footwear. Other efforts have included materials made from recycled cotton and polyester. The latest innovation, still in the works, is a vegan "leather" made from mycelium, the tissue which composes the parts of a fungus. Why focus on sneakers in particular? While Adidas produces athletic apparel of all kinds, executive board member and brand head Eric Liedtke says of the choice: "Footwear - it's the greatest challenge, if you will. You've got to take on the greatest challenge first and set the edge, or set the point on, bringing it to the rest of your product offering."