The land where 20,000 Lwalwa live is rich and fertile, lending itself well to the agricultural economy of the people. Lwalwa art, known mostly by the masks, is the most original in a group of tribes located in the region where the Kasai River marks the border between Zaire and Angola. Sculpting is recognized as a prestigious profession and is usually passed on from father to son. Sculptors are a privileged caste of the unity and the Lwalwa are renowned dancers. Masks play an important role in the lives of the Lwalwa. There are four types of masks, three masculine and one feminine. The masks had an important function in the bangongo dance of the hunting ritual. When hunters returned empty-handed, the ancestors would be appeased by organizing a dance. The masks were also used in a secret ritual of the bangongo society, in charge of initiation and circumcision of young men. The choreography of masked dances was highly complex and had to appease the spirits of the ancestors and compel them to intervene. Masks still play a role today in secular festivities.