Human beings have largely transitioned from a nomadic to more sedentary, urban way of life. Cities however tend to generate their own forms of movement, both horizontal and vertical. In order to function cities require air, light, water: they must breathe, accommodate continuous flow, sustain renewal. While cities throughout time have struggled with high densities, these challenges are proof of their attractiveness. The combination of high densities and robust topography is what produced the network of elevated walkways in the central business district of Hong Kong Island. This thesis researches an as-yet-unrealized but inevitable fourth generation (4G) circulation system for Hong Kong’s downtown core. While primarily for pedestrians, this new circulation layer will be physically and functionally distinguishable from the city’s current network of elevated walkways. While the latter only brushes past towers’ façades, this proposal has the audacity of merging with the architecture, refurbishing in consequence its interior layout.