Babylon is a sustainable building design which not only fulfils urban needs for more residential and office space in the city, but also promotes social and environmental sustainability in buildings of the future. By stacking a variation of lifestyles and functions, new social interactions can occur in the atrium, also a 3-dimensional park, which becomes a social space capable of nurturing new community relationships. With regard to environmental sustainability, the greenhouse function of the atrium not only saves energy and heating while providing natural ventilation, but illustrates the aesthetic and functional qualities that ecological buildings can have. In this way the main social space of the building is also its ecological core, and these two sustainable aspects are united and manifested in a single space. At a larger scale the compactness of the building frees up surrounding urban space for much-needed public spaces while also minimising traffic-related problems.