What would the ocean sound like if it could play an instrument? A 230-foot-long structure on the coast of Croatia allows water from the Adriatic Sea to flow into specially-built chambers, creating a pipe-organ-like effect (as you can see from this image from Flickr’s @linssimato). The structure’s been around since 2005, but thanks to recent posts on BoredPanda and Upworthy, it has gotten some viral attention this week. You can listen to the Sea Organ in action below.