[Image: A swiftlet nesting house in Thailand; photo by Alexander S. Heitkamp, courtesy of Wikipedia].

"This drab, windowless concrete facade does not conceal an electricity substation, data servers, or a high security detention center," Nicola Twilley writes over at GOOD. It is, instead, a living birds' nest factory, an emerging building type that has "spread across Malaysia, Thailand, Vietnam, and even Cambodia, towering above traditional one-story structures and transforming the urban landscape." Their purpose? To foster the production of swiftlet nests, used in Chinese bird's nest soup.

Nicola explains that these nest farms are, in effect, surrogate geological formations: "the buildings are intended to mimic caves," she writes, where the swiftlets would normally live, "with a carefully spaced matrix of wooden rafters replacing the ledges and crannies of a cave ceiling, and detailed attention paid to internal temperature, humidity, and even sound."

They are, in effect, part of what could be called a saliva industry, as the nests are made from swiftlet saliva. A spitshop, say, instead of a sweatshop. Mechanize this one step further, and full-scale 3D saliva-printing might not be far off...