China's cities are growing at a rapid pace, and therefore getting denser by the day. In order to accommodate this upward extrusion of the city and the urban circulation problems it brings with it, designers are looking to layer more transport corridors vertically above and below ground. One example is the Shenzhen Bay Super City - Xtremendous by UNIT Urban New Idea Team.

The almost 500-foot (152-meter)-high walkways will connect the individual towers, uniting them into an integrated urban environment and leaving the street open to incorporate with nature. An open green space alongside cultural facilities, indoor fair and trade area, and commercial spaces will invigorate the decongested streets for year-round activity.

The walkway in the sky has had somewhat of a resurgence in the last decade, after falling out of favor after Brutalism and Portman's hotels. The most noticeable similarities are with the proposal for the unbuilt World Trade Center Memorial and Towers by United Architects that tied together a series of towers with a strip of connective space.

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