Kulning: a unique style of singing/calling used to call the cows and goats down from high mountain pastures where they have been grazing during the day. It has its roots in the Nordic medieval age.
Traditionally, it was employed outdoors, to call animals or to communicate with other people over long distances. The sound is intense, concentrated and piercing.
In Scandinavian countries, each family of herders would have its own call, or kulokker, to which that herd would respond. The shepherdesses would make their own kulning call, then listen for the bells of their animals as they started back downhill toward them. When wondering what people did before modern communications technology, here is one answer. They developed incredibly beautiful musical calls that sing through the mountains.