La Gomera is one of Spanish Canary Islands. Due to rough island landscape it was not always easy to travel. That is why the locals found an unusual way of communicating to each other. For centuries they have been doing it by whistling. Their whistling language is called Silbo Gomero (Gomeran Whistle) or just el silbo (the whistle).
A "silbado" or "whistler" is a person speaking the language. In time number of people using the whistling language dropped significantly. To somehow protect this unique tradition all kids of La Gomera learn it in school. The monument to the language can be seen in the village of Igualero.