The modern custom of exchanging wedding rings dates back hundreds of years, originating in Europe. The ring is traditionally worn on the ring finger of the left hand, as it was believed that this finger had a direct connection to the wearer's heart. Furthermore, it is said that that the wedding ring represents the unbroken circle of love, with no beginning and no end.
Though most wedding rings are gold, I've seen many (especially the groom's ring) that are made from other metals, such as tungsten or platinum, and have even had a few instances where it was made from a completely non-typical material such as wood.
Interestingly, only the bride originally wore a wedding ring, with the tradition evolving in the United States of America in the mid-20th century to also include a ring for the groom.
Location: New Orleans, Louisiana.