In the large oval bezel of a fine Syrian ring is set a paste representing a topaz. The shoulders expand to form the bezel. This ring, the lower half of which has been broken off, shows an exceptionally fine patina; it was of large size and must have been a striking ornament on the wearer’s hand. As the broad oval extends across the hoop, not at right angles with it, it must have interfered slightly with a free use of the fingers near the one on which the ring was worn. In the Philippine Islands a type of ring that is made by the natives has a number of spiral twists, from five to as many as a dozen coils appearing in these rings. The serpentine form is accentuated by a pattern of dots or cross-marking, with sometimes the indication of a conventional flower design. While rather clumsy for wear, these rings still possess a certain artistic quality. Fine examples are in the Ethnological Department of the American Museum of Natural History, New York City. The ancient city of refuge, Machu Picchu, probably built by the Incas nearly 2000 years ago on a Peruvian mountain top, was uncovered by the National Geographic Society--Yale University Peruvian Expedition of 1912, of which Dr. Hiram Bingham was the director. Among the many interesting relics found on this unique site were some silver rings, one being of the twisted type, with the ends free, so as to suit the size of any finger, while another has been welded or hammered into a closed circlet. While it is impossible to date these rings with any approach to exactness, they are undoubtedly examples of the art of native Peruvian silversmiths prior to the Spanish Conquest.[138] Rings in great variety are worn in the Congo region and in every part of Bantu and Negro Africa. There are heavy rings and light ones, simple hoops and spirals, and they are worn on neck, arm, leg, finger and toe. They are made of brass, copper, ivory, iron, elephant foot-pad, and several other materials. At Akkra, and in Liberia, there is quite a manufacture of gold rings, and, to a lesser extent, of silver rings also.[139]