Zadar's Sea Organ, played by the waves

Sitting on the waterfront steps, you hear low notes mingle with the approaching waves. It sounds as if someone might be playing keys out of sight, but waves and tides drive Zadar's Sea Organ, or Morske orgulje, in Croatia. The place from which you watch the sea is part of the instrument.

According to the Zadar Tourist Board, the installation extends along about 70 meters of waterfront. Beneath it are 35 pipes of different lengths, diameters, and slopes. Rather than standing on the steps, the instrument is built into the waterfront where people sit and walk. From outside, the sea and steps are what you notice first.

The waves move air through the pipes to produce sound. Instead of a musician keeping a steady beat, the timing and strength of the waves shape the performance. No recording loops over and over. The changing movement of the sea reaches your ears through the pipes.

The pipes' differing lengths and widths matter: they are not all designed to produce the same note. As they respond to the irregular movement of the water, the sounds of the instrument mingle with those of the waves. The music joins the natural sound rather than replacing it.

The neighboring Greeting to the Sun installation is known for light; the Sea Organ invites listening. A travel photograph can preserve the shape of the steps, but not the sounds made by those particular waves. Returning to the same waterfront will not bring back an identical performance.

There is no auditorium entrance or prescribed order for watching. You can simply sit on a step and wait for the water to come in. The next note is up to the sea.