UNStudio and COX Architecture's proposal for the Southbank area and Melbourne is integrally organised by a ‘Green Spine’ of vertically networked platforms, terraces and verandas. This multifaceted spine is created by the splitting open of the potential single mass at its core, thereby forming two separate highrise structures and causing them to reveal the almost geological strata of their core layers as they rise above a light-filled canyon. As a result, the towers that emerge on either side can enjoy porous city views and vastly improved contextual links, while the residences, offices and the hotel benefit from increased daylight and access to outdoor spaces. The orientation of the Green Spine further enables an extension of the public realm on the podium, the continuation of green onto the towers and facilitates orientation to the CBD and the Botanical Garden at the top of the towers. The taller tower will be entirely residential and reach a height of 356.2 metres. This tower will house a publicly accessible garden at its top. The lower tower will be home to a hotel and commercial space and top out at 252.2 metres. In addition to being fully integrated within the existing Melbourne network of cultural, entertainment, leisure and commercial venues on offer, the design further proposes a mixed-use building that is a city in itself. A host of programmes, including recreation, retail, offices, residential, hotel and exhibition spaces are integrated into the vertically stepped public infrastructure.