Some types of African masks are on exhibit in Omidvar Brothers Museum which were brought by Omidvar Brothers from some African tribes.
Indigenous people of different African tribes and also lots of people in the world believe in the secret powers of the nature and think that they have relationship with spirits.
They believe that masks can fascinate super natural power for them and while wearing these masks, the wizard of the tribe can summon good spirits and banish dirty ghosts from his tribe and region.
In some kinds of these ceremonies, the wizard wears grass, fights with the dirty ghosts and when he goes down in trance, he enters his existential soul.