A horseshoe is a fabricated product, normally made of metal, although sometimes made partially or wholly of modern synthetic materials, designed to protect a horse's hoof from wear. Shoes are attached on the palmar surface (ground side) of the hooves, usually nailed through the insensitive hoof wall that is anatomically akin to the human toenail, although much larger and thicker. However, there are also cases where shoes are glued. Some believe that to hang it with the ends pointing upwards is good luck as it acts as a storage container of sorts for any good luck that happens to be floating by, whereas to hang it with the ends pointing down, is bad luck as all the good luck will fall out