A wedding ring or wedding band is a ring, often but not always made of metal, indicating the wearer is married. Depending on the local culture, it is worn on the base of the right or the left ring finger. The custom of wearing such a ring has spread widely beyond its origin in Europe. In the United States, wedding rings were originally worn only by wives, but during the 20th century they became customary in that country for both husbands and wives. It is a tradition that goes back many centuries, having manifested in the wedding customs of many different nations and religious groups. They come in many forms, most traditionally a ring made of gold or some other precious metal.