Last February, when Tobias Berger took the stage at a Manila art fair to introduce the Old Bailey Galleries, a new contemporary art centre he runs in Hong Kong, the German curator gave the audience a bit of cultural and geographic context – starting not with Hong Kong but with Shenzhen, the Chinese mega-city just across the border from Hong Kong. “Shenzhen is the most exciting city in the world right now,” he enthused.

It’s easy to see why. While Hong Kong struggles with the same problems as any economically mature city, its sister city is growing at a spectacular rate. Home to an estimated 18 million people, Shenzhen is China’s richest city, with a per capita GDP of US$23,749 – higher than a number of European countries, including Portugal and the Czech Republic. And it’s as close as a city can get to being a blank slate. When it was founded as a Special Economic Zone in 1980, it was a rural backwater. Hong Kong investors and state owned enterprises opened factories, and migrants from across China soon flooded in to work. The seeds of China’s modern-day industrial revolution were planted in Shenzhen.

Now it has moved onto yet another stage of development. While suburban factories produce the world’s sophisticated electronics, the city centre has been taken over by service industries – especially tech firms such as Tencent, maker of China’s ubiquitous WeChat app, and market-leading drone makers DJI. A huge network of designers take advantage of open source hardware to create new products at an astonishing rate.

Vast projects are the norm in Shenzhen. Supertall skyscrapers are popping up in new business districts all over the city, like the 350-metre Hanking Center Tower, designed by US-based firm Morphosis, which topped out last December. Even public utilities are ambitious: Danish firms Gottlieb Paludan Architects and Schmidt Hammer Lassen Architects have designed the world’s largest waste-to-energy plant for a site on the outskirts of Shenzhen – a circular structure that will be covered in 66,000 square metres of solar panels.

Leisure is front and centre in many of the new developments. “After such huge growth they’re now realising they need to improve it by focusing more on quality of life,” says Jacob van Rijs, a founding partner of Dutch firm MVRDV. In many cases, it’s private and state-owned developers that are leading the way; companies that once built factories and cookie-cutter housing estates are now building sophisticated lifestyle developments.

OCT Group is one example. In the mid-1980s, it developed a large swathe of land into a working-class industrial enclave; two decades later, it hired local firm Urbanus to convert one of its old factory zones into a creative hub called OCT Loft . With little money but lots of creative freedom, the architects focused most of their energy on the public spaces, replacing concrete with brick, planting trees and building steel canopies to provide shelter and a coherent visual identity. “When people came, they were surprised it was so raw,” says Urbanus co-founder Liu Xiaodu, who worked on the project with his partner, Meng Yan.

It turned out to be a hit – something completely unlike the giant shopping malls that were becoming common in Shenzhen in the 2000s. A few years after the initial renovation, OCT commissioned Urbanus to expand the cultural district, this time with a larger budget. It now spans 150,000 square metres, including design studios, bars and restaurants, shops and 3,000 square metres of exhibition space. The firm is now working on converting B10, a former industrial block, into yet another art hall, which will add 8,200 square metres of exhibition space to the district.

Another state-owned enterprise, China Merchants Group, is doing something similar in the former industrial district of Shekou. Pritzker-winning Japanese architect Fumihiko Maki won a competition to create a cultural hub in the formerly industrial neighbourhood of Shekou that will house a new V&A gallery (see p116). Elsewhere in Shenzhen, MVRDV is working on an athletic centre and theatre (p114); Mecanoo, has designed a complex of three cultural centres and a book mall (p117), while KSP is designing a new art museum and library (p116).

Urbanus has finished the design for a neighbourhood sports and cultural centre, which stacks each of its facilities on top of one another in a Jenga-like tower, with outdoor public space in between. Meng Yan says it was a response to a brief that called for 38,000 square metres of floor space on a 5,700 square metre plot. “I realised it is a rare opportunity to develop a stacking hybrid building with vertically articulated public spaces,” he says

Most of these projects are enormous: Mecanoo’s cultural centres and book mall spans 99,000 square metres. KSP’s Shenzhen Art Museum and Library will contain 15,000 square metres of exhibition space – larger than London’s Tate Modern and New York’s Museum of Metropolitan Art, and about the same size as Hong Kong’s much-hyped M+ Museum.

Each project makes an effort to break up their structures into different volumes with plenty of public space in between. Reinsch says it’s a way to avoid creating yet another one of the overwhelming megastructures that are so common in Shenzhen. “For us, as architects, it’s not just about space, but about creating an environment for social interaction,” says Reinsch. “The scale in China can be a problem, because you don’t have human-scaled spaces. The challenge is to create spaces that make you feel comfortable, not lost.”