Spring is in the air at the Promenade des Artistes

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An impressive collective musical instrument, 30,000 square feet (and not a foot less!) in size, has been under construction at the Promenade des Artistes since the beginning of the week. From now until its official unveiling on April 21, we'll be offering hints of its final, breathtaking form, both on our Facebook page, and via the #21B hashtag on Twitter.

For your first hint, here's a photo:

Any idea of the concept?