The Sea organ in Zadar, Croatia, is an architectural sound art object and an experimental musical instrument, which plays music by way of sea waves and tubes located underneath a set of large marble steps.
The organ buried in the promenade makes a haunting but harmonious sound through the motion of the sea.
Driven by waves this organ creates notes at random. Despite the unpredictability of the sounds, overall what is heard is surprisingly harmonious. This happens because the different organ pipes have been carefully tuned to only produce certain musical notes that sound good together.
It is seventy meters long and has thirty-five organ pipes built under the concrete. As you move along the promenade the sounds and harmonies change. The movement of the waves push air in and out of the organ pipes to create the notes.