ritual

"This is consistent ith the tradition of many ancient cultures to capture natural sounds in musical instruments, and could explain the ritual dimension of the death whistle sound for mimicking mythological entities," explains Frühholz.

Harvesting olives is an age-old ritual and also an economic necessity for many Palestinians, but, according to the UN, it is increasingly precarious.

Most Nagas now follow Christianity, but their ancestors were animists who followed different birth and death rituals.

A University of South Florida professor found the first-ever physical evidence of hallucinogens in an Egyptian mug, validating written records and centuries-old myths of ancient Egyptian rituals and practices.

"Adverts have become part of the ritual surrounding Christmas," Prof Helen Wheatley, a historian of television, told BBC News.