Part of the 14 Cities series:

"Floating low over the Blue Mountains, the city of Tillandsia is named after a very particular plant genus. 

Tillandsia — the plant — draws moisture and nutrients direct from the air itself (from dust, decaying leaves and insect matter), and so this air plant serves as both metaphor and native flora for the city.

Borne aloft on warm thermals rising around the Three Sisters, Tillandsia appears as a cloud of bubbles, its numerous sacs glowing with LED lighting and humming with activity. The bubbles are composed of ETFE and aerogel, the latter material lighter-than-air. Its gently twirling rotors are powered by solar energy harvested on the skin of the structures, and wind energy gathered by high-altitude kites. Thin guylines ascend into near-orbit above the floating city, also traced with arcs of lighting to warn nearby aircraft. At night, the structures look like a large cloud lit by internal lightning.

Tillandsia’s small but wealthy population has taken to the air, a stated attempt to ascend to a higher form of humanity, though they spend most of their time circling around the east coast of Australia they originally ascended from, where their plants can thrive and from where they can occasionally descend on small elevator pods, touching base with rural communities to exchange goods and services."

Notes: An idea which rather obviously grows out of the CLOUD project I was involved with, and some of Tomas Saraceno's ideas. The tillandsia genus is indeed known as aerophytes, or air plants. As with the Gold Coast floating city, though air-borne rather than water-borne, a fairly well-trodden path in terms of utopian urban visions. I'd love to see such a thing hovering around the Three Sisters, however.