This 230-foot-long musical instrument contains 35 organ pipes and is powered by the Adriatic Sea, producing sounds for visitors that seem eerily composed rather than random.

Whistle holes cut into the stone steps are ‘powered’ by air pushed in by waves of water, creating chords that are strikingly harmonious in nature. The sounds are constantly shifting, but you can listen to a clip above (a .wav file of the waves, if you will).

The Sea Organ, or the Morske Orgulje, is part of plan to revive Zadar, a city over 3,000 years old that was nearly obliterated in the Second World War. Architect Nikola Baši? wanted to give the place something with character, differentiated from the stark and boring concrete buildings that were created during initial years of rebuilding.

The design was inspired by the Hydraulis, an ancient Greek instrument that used water to push air through tuned pipes, but also borrows from the Wave Organ in San Francisco, a likewise seaside device amplifying the sounds of the Pacific Ocean. (images by linssimato, Lisa and J We).

Leaving those stand-up paddleboarders in the proverbial dust, these new battery-powered boards will let you cruise lakes, rivers, cannals and other bodies of water all without that formerly-critical ingredient: waves.

The Spanish surf company Onean has unveiled two models, the Carver and Manta, respectively designed for serious surfers to slalom across calm water and to let more casual surfers to smoothly explore still surfaces in remote places.

Each version has speed controls tied to a handheld remote and optional foot slots for greater traction. A third model, the Blade, is also in production but details about the board have yet to be released.

The Carver owes its look to the classic longboard and its speed (around 5 miles per hour) to an interchangeable onboard battery powering an axial water pump. The wider Manta has is slightly slower and wider, made for cruising.

The battery life on the faster variant is only 20 minutes, at which point it can be swapped with a spare, but the latter has more energy storage, allowing for up to 2 hours of travel and enabling more ambitious explorations.

Aside from obvious coastal uses (like providing a backup board on calm days at the beach), electric boards can bring an entirely new sport to landlocked but water-covered places like Minnesota, the Land of 10,000 Lakes.

Many of the most densely-populated cities in the world reside along bodies of water, from canals and sounds to seas and oceans. Beyond merely extending solid ground, this three-island project creates new mobile infrastructure right out on the waves.

In the case of Seoul, the Han River (spanned only by periodic fast-paced bridges) splits the city down the middle. To bridge the gap, this bold new project by New York firm H Architecture establishes institutional uses stunning in architectural style and engineering audacity. Each island  floats on pontoons, carefully anchored against gravity, wind and water loads, capable of withstanding monsoons.

ArchDaily summarizes the scope of the project: “Programmatically, the islands contain several cultural, educational, and recreational functions. They will be the venue for many featured events in the city. The design concept stems from the stages of a blooming flower: a seed, bud, and blossom. Each of the islands take on the form of one of these stages, manifesting as delicate yet bold structures of glass, wood, and steel.”

The smallest island (Terra) revolves around water sports, with club rooms, rooftop terraces and water slides. The next island (Viva) takes entertainment up a level, with performance and exhibit spaces. The largest (Vista) features a huge indoor space for festivals, concerts and plays. Together, they also add visual interest, both day and night, to this heretofore untapped source of potential skyline.