Silbo Gomero

Silbo Gomero, the whistled language used on La gomera, was in danger of diying out at the end of the 20th century. then, the islanders worked to preserve it. In 1999, UNESCO declared it a "masterpiece of intangible cultural heritage". Watch how children practise "silbo" at school.

http://www.bbc.com/news/magazine-20953138