Indigenous people of Mentawai, living isolated into the jungle, are culturally and spiritually different from the Indonesian people of the mainland. Mentawai observe their own traditional religion called "Arat Sabulungan", which literally means "religion of leaves" to indicate the importance of the forest. Arat Sabulungan has been practiced for centuries and regulate the relationships between humans and the spirits of Nature to live in harmony and peace into the jungle.