The “ground plane” is an important reference in architecture. The ground is typically where people walk. The ground is where our fabricated buildings meet the earth. And the ground is where our experience of the urban environment–however good or bad it may be–truly takes shape. Often times I feel that we, city dwellers, spend far too much time worrying about the height of buildings and not enough time worry about the ground floor.

But what if there were no clearly defined ground plane? This morning I stumbled upon an interesting book called, Cities Without Ground: A Hong Kong Guidebook. The authors call it “a manifesto for a new theory of urban form.” And the argument is that Hong Kong has developed a unique series of public/private spaces that allow it to function as a fully three-dimensional city. 

Through underground tunnels, above ground walkways, escalators, and other connective infrastructure, Hong Kong is reinventing the way we typically think about cities–both from a user experience and a real estate standpoint. Here’s an excerpt from the Guardian architecture and design blog:

The phenomenon began in the 1960s, when the Hongkong Land company, one of the main developers in the region, built an elevated walkway to connect a luxury hotel to the second storey of an adjacent shopping mall. An insignificant move, perhaps, but it in fact had the effect of changing the rentable values within the building: suddenly the mall’s second floor units could be rented out for more than those at ground level. It entirely recalibrated the vertical logic of real estate value.

Now, you could argue that Hong Kong is a unique place. And it is. Other, less dense cities, have found above and below grade walkways to be a destroyer of urban vibrancy. But in Hong Kong it works and, as many other cities around the world focus their energies on urban intensification, we may find that Hong Kong is indeed a new model for urban form.