Behind the somewhat awkward name of the Bi-City Biennale of Urbanism\Architecture (UABB) in Shenzhen and Hong Kong—now in its sixth and fifth editions, respectively—lies a correspondingly awkward reality. The event is ostensibly a cross-border collaboration between the two adjacent metropolises, whose urban and economic synergies within China's Pearl River Delta region have been the subject of endless scrutiny and speculation. However, one of the most noticeable, recurring traits of this dual biennale has been how little the two sides actually interact. It’s a disconnect that can draw the region’s convoluted dynamics into sharper relief.

And so it was at this year’s edition, which runs until February 28. The Hong Kong side, dwarfed by its larger and better-funded mainland counterpart, curated by a team led by Christine Hawley, nevertheless manages to assemble an array of tantalizing eye candy in the city's Kowloon Park. There’s Very MK's urban farm, Kacey Wong's mobile mojito bar, and a schedule of public workshops "to bring in the emphasis on local community that we wanted," says Sarah Lee, one of the curators. But anticipating the Hong Kong of 35 years from now, Visions 2050—Lifestyle and the City, as the exhibition is themed, stands out mostly for the aquapolises and geodesic domes, “smart nodes,” and plug-in pods that present a polished, if somewhat retro-futuristic, prospect for the city.

However, all that technocratic optimism feels somehow out-of-place in a city plagued by so many problems: political dysfunction, growing insularism, a skittish economy and, especially, an increasingly tense relationship with mainland China that erupted during the Umbrella Movement protests that shut down large swathes of Hong Kong in late 2014. At a time when many Hong Kongers sense creeping self-censorship, Visions 2050, with its mostly Hong Kong-specific projects by local architects, errs on the side of politeness. And so there’s an odd symmetry in the fact that it’s over the mainland Chinese border, in Shenzhen—that booming hothouse of start-ups, drone-makers, and maker labs whose economy is expected to surpass Hong Kong’s—that the biennale takes on a more international, urgent and, occasionally, subversive tone.

Call it what you will: informal, co-designed, social-practice, inclusive, guerilla, activist or, more broadly, tactical. Lying somewhere between “architecture without architects” and “architecture beyond building,” the Shenzhen side of the biennale ventures expansively into the realm of architecture as social engagement. Entitled Re-Living the City, the exhibition occupies a former flour mill—impressively retrofitted for the event by architect Doreen Liu, a biennale co-curator—with what is essentially a critique of the kinds of top-down practices that are particularly salient (and politically loaded) in places like, well, China.

Arguing that “we have enough stuff…we do not need to make or build any more,” lead curator Aaron Betsky and his team have brought together sections ranging from Betsky’s own “Collage City,” with its salvage-chic, found-object installations (though sadly, the biennale venue itself will likely be torn down for new development, despite its renovation) to a plethora of build-your-own-city, grassroots, and speculative projects, alongside the requisite nods to maker culture, by both Chinese and non-Chinese participants.

Proposing micro-interventions and encouraging children to imagine their ideal city is hardly threatening stuff. But despite being a Chinese government initiative, the biennale boldly pushes its bottom-up ethos into the territory of resistance and activism. Examples include Manuel Herz’s study of a refugee camp turned self-declared, independent state in Algeria, which won the biennale’s top prize (disclosure: I was on the jury), Santiago Cirugeda’s barely-legal guerilla architecture in Seville, and “Occupy Beigang,” the story of a homeless migrant who claimed an unused plot of land for himself in a provincial Chinese city.

Hong Kong’s Occupy-style Umbrella Movement also makes a notable appearance—in Shenzhen. Rotterdam-based Crimson Architectural Historians included it in a sprawling illustration it presented of protest movements around the world. That the censors disapproved was easily predictable. Yet in a remarkable, if perverse, display of transparency, the overall work remained on view; the offending section is simply covered in white fabric.