Bernard Castelein / Nyapo 'the fisherman', mask used in Aji Lhamu dance. The hair is of a 'wild' sheep, called Raruk. Rupa Gompa Museum, Rupa, Arunachal Pradesh, India.

Bryan and Cherry Alexander / Miniature ritual mask carved from Walrus ivory (circa 1000 BC - 1000 AD) Bering Strait, Chukotka, Siberia, Russia.

Bryan and Cherry Alexander / Nganasan man wearing traditional clothing made from reindeer / caribou skin and Shaman's headdress. Taymyr, Northern Siberia, Russia, 2004.

Bernard Castelein / Traditional masks (worm by Buddhists during Lama dances), Melamchigaon, Helambu region, Nepal, November 2009

Philippe Clement / Traditional Tschäggätta mask, Lötschental, Switzerland

Jouan & Rius / Young San Bushman with face decoration of oryx mask, Bushmanland, Namibia

Pete Oxford / Local woman with sandalwood face mask - used as sun protection and a beautification. Isalo National Park, MADAGASCAR 2005

Bernard Castelein / Nepalese monk with face mask, dressed as Demon (to reprasent evil) at the end of the 'Duk chu' festival, Lo-Manthang, Upper Mustang, Nepal

Bernard Castelein / Close-up of Nepalese monk wearing face mask, dressed as a Demon, during 'Duk chu' festival, Lo-Manthang, Upper Mustang, Nepal

Bernard Castelein / Close-up of Nepalese monk with mask, dressed as a Demon during 'Duk chu' festival, Lo-Manthang, Upper Mustang, Nepal

Doug Perrine / Blue face / yellow mask angelfish {Pomacanthus xanthometopon} Ari Atoll, Maldives

Pete Oxford / Therapeutic mud mask from sulphur lake, Machalilla NP, Ecuador