Air-tight, the futuristic LED-lit bubbles not only act as adjustable insulators, turning the building into a greenhouse, but also serve as storehouses for warm air that can be pumped into the Cube as needed. Though it's only .008 of an inch thick, ETFE, which has been used to a lesser extent in the UK's Eden Project and Germany's Allianz Arena can hold up to 300 times its weight. Without trussing, it can span greater distances than glass, and costs up to 70 percent less to install. Though critics say it will need frequent scrubbing (Beijing's grit had clearly left its mark on the building today), the material is billed as more self-cleaning than glass, and can be recycled.

But the Cube's facade probably won't need to be recycled any time soon. Unlike the similarly stunning, steel-encumbered National Stadium nearby, which some fear could go from a "Bird's Nest" (its nickname) to a "white elephant" once the Games are done, the Water Cube is set for a lengthy, sustainable afterlife (its construction hasn't killed anybody either, at least officially). "What it is for the next 30 years is more crucial than what it is during the Olympics," PTW's John Pauline, one of the building's lead architects, tells Treehugger.

"It's very common in Olympic planning to focus on the now rather than the future. More important is what happens in the next phase [of the Water Cube's life]," which will see the building converted into a recreation center for nearby residents. "We dedicated only a third of the Water Cube to the swimming pool. When visitors come after the Olympics, they'll be able to play a game of tennis, go on the waterslide, and so on." Upstairs, the Cube features a cafe.

Though its design has been criticized by some as "not Chinese enough," the building, which was designed in cooperation with a Chinese design institute, is modeled in part on the rectilinear shapes of traditional Chinese architecture: Beijing's courtyard homes, the old city wall, and the Forbidden City are all rectangular in shape. Meanwhile, says Pauline, the Cube balances out the Olympic green, serving as yin to the stadium's yang. "There's this real tension in duality that begins to occur. I think it happens in a really good way," he says. Since it started, the building has garnered a bevy of awards, including one from Popular Science and the Venice Biennial.

Water is, naturally, also a focus of the building's sustainability efforts. A rainwater collection system gathers 10,000 cubic meters of the wet stuff each year, while a recycling system reuses 80% of the building's water. That's crucial in drought-plagued Beijing, which has less water per person than Israel.

Indeed, the Water Cube serves as the symbolic centerpiece of the Olympic committee's "Green Olympics" campaign, which may be as much of a propaganda job as it is a valuable consciousness-raising effort.

Altogether the Olympic venues are said to have a combined 121 water-efficiency projects, saving a total of over 1 million tons of water per year, and feature a plethora of energy-efficient measures like solar panels and light piping that help the buildings exceed new national energy standards.

But even if the "Green Olympics" are a green wash -- and some Olympic teams aren't taking their chances -- the Water Cube will likely stand out as a luminous model of green design, and one that won't fade with the closing ceremonies.

Discovery Channel has video...

... and so does Arup.

See also Daily Mail, Vector Foiltec, Arup, and PTW. PTW's John Bilmon talks about the design with CNN.

Also on Treehugger:
Attack of the Green Monster, World's Largest Solar Stadium, Solar Stadium for 2009 World Games, First Eco Football Stadium, ISPO Focuses on Eco Design.

Photos courtesy of Arup, PTW, China.org.cn, Chris Bosse and the Daily Mail.