Combine a park with native plants atop a railroad trestle, intimate views of New York buildings and the Hudson River, and the music of zen gongs, twinkly sounds, electric guitars and compositions by several musicians from their smartphones matching (some of) the footsteps of walkers, and you have the event coming up at New York City's High Line on Dec. 21, according to a release.

It's called The Gaits: A Winter Soundtrack, and will involve a free, downloadable smartphone app composed by Lainie Fefferman, Jascha Narveson and Cameron Britt. As the groups walk they'll hear instead of footfalls the sounds of water splashes, dulcimer notes, guitar chords and car horns that -- surprise -- don't actually come from the street below. Heck, there'll even be the sound of applause, which we all need from time to time.

The event is sponsored by Make Music New York, Friends of the High Line and will feature software development by Daniel Iglesia. MATA, an organization for emerging composers, is also behind it.

If you're in the area, you can download the iPhone or Android application and arrive at 5:00 PM. Participants will start out on street level below the High Line at Gansevoort and Washington Streets, head through the park, and finish up at West 30th Street.

Some folks will also have small portable speakers. Please bring one if you have it. The first 100 walkers to arrive will be able to borrow a free, wearable speaker for the event.

The High Line is free, and the event will take place rain or shine.

Other music walks include Unsilent Night, which features music by Phil Kline and takes place in a long list of cities in North America. It started in New York, where it took place earlier this year from the West to the East Village. It also sets off in Houston, North Battleford, Saskatchewan; and Knoxville, Tenn.

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