The Asmat Tribe of Indonesia is known for it's tradition of septum piercing. Some of the largest septum piercings in the world are to be found adorning the faces of the Asmat people.
Sometimes the rings are made from carved sea shells. Other times, they would use the leg bone of a pig or more shockingly, the tibia bone of a human enemy slain in battle! These bone plugs could be as large as 25mm and are known as "Otsj."